From what I have seen yes, they are the sniper svt's. The notch locks it all together. Take alook at west rifle for some good looking ones. The normal SVT-40's cost a little less from what I have seen...by about 50 bucks.
Edit: Info from Wiki
Total production of the SVT-38/40 was 5,772,085 rifles, of which 51,710 were the SVT-40 sniper variant. In service, SVTs frequently suffered from vertical shot dispersion. For a sniper rifle, this was unacceptable, and production of the specialized sniper variant of the SVT was terminated in 1942
Link ht tp://en.wikipedia.org/wiki/SVT-40#Towards_the_SVT-40