Welcome to the board scubaman.
Yes, you have a '56 letter gun there. Looks 'as-issued' to me, but I would need to see some detail of the stock S/N area (and any cartouche on the right side...hard to say if there is an acceptance stamp on there in one of your photos?), trigger group matching S/N, magazine matching S/N and bolt matching S/N before I would feel comfortable enough to make that call 100%.
It's a very nice specimen though. The laminated stock is the correct color, the handguard matches, the metal has the correct blued luster, bayo is gold with an EP'd number, and the receiver cover has the correct two toned bluing with matching font on the stamped S/N. Others here may have additional insights.