Mounting sights on a receiver is convenient, not optimal. And you don't know that. Yes, the inherent inaccuracy introduced by putting the rear sight/scope on a different part of the gun, one with its own stuff going on, than where the bullet actually travels may be offset by the longer sight radius compensating. With a scope? Try a forward-mounted long eye-relief one. That the novices here really don't understand why so many rear sights are mounted on barrels is surprising.
Being around awhile with narrow and shallow experience doesn't get you anywhere either. Sights not being on a receiver is such a well known and old issue that knowledgeable people here probably won't even bother to comment -- it would just be another dopey circular internet e-Mail trail with people defending what they have in their hand or want to be true vs. reality.