It could also mean that the men readjusted the flip up leaf sights for no elevation. The first graduation on an enfield rear sight is 500 yards if memory serves me correct. I would check my original enfield but the rear sight is missing (no kidding). The main reason that some enfields are missing the rear sight is that it was soldered on. Somewhat easier to knock off than a springfield which is attached with a screw. On the other hand, once you are used to shooting a smoothbore without a rear sight, you may consider a rear sight unnecessary.

Interesting post.