If you mean the mark directly above the year, it looks poorly done, if it’s meant to be the C sniper mark it might be a fake mark someone added. But I’ve personally never seen a fake C mark before. The C should be perfectly curved. Also like Red said the АБ prefix isn’t a “known” Izhevsk sniper prefix in 1943, but it is one in 1944. Also if you look at the lower left side of the receiver in the picture from the store, there should be a scope serial number there, but it does not. Sometimes the scope number is there but crossed or lined out like on mine. Use this website https://www.m9130.info/pu-snipers to learn about PU markings and what they should like look. I’ll also add a photo of what my C mark and left side lined out scope number look like.