How similar are these to the FPK scopes? Do they need modified or will these scopes fit on a standard side rail. Can they be adapted or no?

I tried to like them years ago but they all sat back way too far and were nearly unusable on an ak unless you had an extra long stock with recoil pad added. I think western optics are a better way to go from a shooter standpoint, especially with the good mounts we have these days.

I put one of these on my M70B1 to keep that ComBloc look and feel . It does pretty well, albeit, sits a bit high and slightly offset to the left. Very clear and bright. I went back to my RSRegulate side mount with modern LPVO for lower-centered and both zero about the same.  If I stick with it it'll mean I probably want to put a cheek riser on but now it's drifting from what I think is appropriate for an AKM.  They will sell you a different base for the mount whether it's for a SVD or AKM style side rail

https://redcolonel.com/pspu-2-5-5x24v-zoom-sniper-scope-for-ak.html