Below is an example of a butt marker disc: Rifle 99 belonging to 7th Battalion, East Yorkshire Regiment and issued in June, 1915. The bayonet issued with the rifle (and checked by the armourer to ensure a good fit) would have had the same markings.
During the Second World War (1941 I think) all brass marker discs and piling swivels were removed from SMLEs and, sadly, most of the identification markings were lost. Virtually all SMLEs on the market nowadays have repro brass discs screwed into the butts.
The surviving marked rifles tend to be those still in service in other parts of the Empire when the scrap order was issued.
Sometimes you find regimental markings stamped into the woodwork; I have a 1912 rifle marked to the Indian 9th Jat Infantry but I have never come across a British unit with markings on the woodwork although some may have done.
I hope this is helpful.
It was standard in the first two years of the Great War for SMLEs to have stock discs and for earlier rifles to be marked on the tang of the butt plate.
After this practice was discontinued, about the only markings stamped in the metal were country ownership (Canada, India, South Africa or Australia) markings and FTR dates, although on Australian rifles you sometimes encounter the state-based military district the rifle was issued to, and sometimes you saw this along with the rifle's serial stamped on the butt.
Fore ends were routinely serial numbered during the Great War, and in Australia as late as 1943, but any rifle which had been through the mill of battle would have have the fore end replaced as the bedding becomes a bit slappy on the inside, and the appearance tatty on the outside.
In Australia it is not uncommon to encounter Great War British made actions re-built as late as 1945 with a complete set of new unnumbered Australian coachwood furniture, Lithgow barrel and often even the bolt has been replaced with an Australian made item and re-numbered ... only the faintest ghost of the original remains.
Intact Great War rifles as they were issued are all but impossible to encounter because had they stayed in the system they would have been routinely upgraded as they wore out, meaning the stock disc would be rendered useless as it was no longer issued to that unit or obsolete, and they would have been replaced with a blank item just to fill the hole, or the hole was plugged with timber, or just left empty.
I have referred to my "Gallipoli rifle" in other posts on this forum, and it has been effectively kept in a time capsule because it was most certainly captured and stored ... according to the stock disc, it was issued in April 1914, and given that it was probably "taken out of the system" by the end of 1915, would have at least required re-barrelling due to wear (believe me, this rifle's seen some work, although some of this may have been in Turkish service), and a new fore end would have been fitted while they were at it due to the long range volley sights being declared obsolescent and slappy bedding.
Meanwhile, by the time of this first required re-build, the stock disc would have been removed as a matter of policy, and the round cocking piece, which is numbered to the rifle, would have also been worn and replaced with a later square one.
And that's just in the first few years of the rifle's life ... had it seen any more heavy service it would have needed another re-build by war's end, and had it soldiered on in Britain it may have been converted to a .22 trainer, in Australia it may have become a HT sniper rifle in 1944 (the pre-war BSA actions were eagerly sought for the conversions) or in India it could have ended up as a single shot .410 shotgun in the hands on a police officer today.
Intriguingly, if the Turks had not have been the ones to pick up this rifles from the battlefield, the rifle may have ended up in Korea with Australian troops in the 1950s (fighting alongside the Turks), on the Western Front with a British battalion or carried by a civilian goat herder (I have seen one example of a 1914 Australian-built rifle where this was almost certainly the case).
As it turned out, it somehow survived intact and was tossed in with a consignment of more modern rifles (nearly all of which had undergone the routine upgrades I descrbed) and ended up in Sydney, Australia ... oh, if these things could talk!
So to sum up, in 30 years of collecting I have only ever encountered one "intact" (meaning in the configuration it left the factory in) Great War rifle, and I'm lucky enough to own it!
Here's the "goat herder's" rifle butt, which had a stock disc for a British unit, but had been very roughly fitted to a 1914 Lithgow:
I had it translated, and was provided with this information:You have to turn the picture to read, because Arabic alphabet is written from right to left.
1. Date of 1340 which means 1922 according to modern calender.
2. The name of owner which is Ismail.
3. Karưndas which means brother (s spelt like sh for example cash)
4. The name of brother's name which is Murat. (They think it's brother's name because of the word "karưndas"). (Murat means wish. So if there wasn't "karưndas" word, it would make sense in a very different way)
5. They are not clear about five. But they think it's "Drama" which is one of the city name which is his birth place (I don't know where it is, somewhere in Rumeli. Because old names had been changed).