Are you talking about an ex sniper? Or just any old mosin with a scope mounted on it?
Yes the mount is quite high. It works, but I prefer the ol irons. Its personal preference though. The finnish sniper Simo Hayha didnt use a scope on his mosin because he believed his head would be too high and expose him to other snipers. Of the over 500 kills he had the kills he had with his mosin, it was all irons.
I have a 1944 ex sniper 91/30, which is a mosin that was a sniper in WW2 but afterwards was converted back to original configuration when it was stored. Mine has an excellent bore with hardly any wear.
On the other hand my cousin has a "sniper" mosin which wasnt a sniper at all in WW2. It was a high wall 1942, but drilled and has a repro scope on it. The bore is a bit dark, and its not as good of a shooter as mine even with a scope to aid in aiming.
Make sure your "sniper" mosin was actually a sniper, and has a good bore on it. The good mosins were hand selected as good shooters and made into snipers in ww2. There are things to look for. Original scopes and mounts are rare.