Nice carbine. I think it is correct. The first adjustable rear sites WRA used were stamped and marked "H" in a shield. Also, If there is any flat grey paint on the rear site, It is a WRA trait.
Although early for this rear site change, this carbine might have been sitting around and a stamped rear site was added before it went out.

See photos for Stamped rear site with some grey paint as used by WRA at about that time period.