I have a 1945 Long Branch T with Ishapore screw and S51 marked buttstock. No S, no DE 6, no SL74 stock. Sniper quality trigger. Serial is 71LXXXX. No mount, no scope. Can this rifle be correct?

I have fitted a very well done mount and a vintage weaver K4 and can tell all it shoots like a T should. Tested with Greek 1970 HXP it shot .75-1.00 inch for 5 shots. Only tested at 100 yards though.