Should I be dissapointed?

[Vlim]

The rear sight has some wear problems, but these are limited to the slider and the sight blade itself. The small notches in the blade, which keep the slider in place, will wear down over time, causing the slider to move during recoil.

Just consider the rear sight to be a 'wear part' and you'll feel less bad. It wouldn't bother me much. My lovely original 1917 arty with matching stock came with an erfurt proofed hold open and a messed up frame serial (in order to get it registered). I'm still very, very happy with it.