Not necessarily. A Corps Signal Company was a different unit to the Divisional Signals Company. He may well have belonged to a Corps Signal Company attached to the Corps that was involved in the battle.
If you look at this page of the London Gazette for MMs you'll see the DSCs and CSCs seem to be treated as separate, as indeed were ARmy Signal Companies:
Vale, 36131 Sjt. B, G., " L " Corps Sig. Coy.
Wainwright, 74043 Cpl. (A./Sjt.) H., "S" Corps Sig. Coy.
Warren, 514031 Cpl. C. H., 567th Army Troops Coy.
Watson, 249612 Spr. G., 34th D.S'. Coy., attd. 160th Bde., R.F.A.
Watson, 101124 Cpl. T. S., M.M., 225th Fd. Coy.
Weller, 89100 2nd Cpl. E. F., 157th Fd. Coy.
Wells, WR/263645 Spr. (A./C.Q.M.S.) C. H., attd. 18th Lt. Rly, Trains Crew Coy.
White, 58208 Spr. A. S. H., 25th D.S. Coy.
White, 70918 Cpl. J. E., 3rd Army Sig. Coy.http://www.gazettes-...&selHonourType=
Note the designations are by letter not Roman numerals...