I haven't checked them. I did find a Cooper 7x57 on Guns America, I think it was but, it looked more like a target rifle than a classic 7x57.
I just checked: made in 1953. If you search the gun library for Mauser, you'll come up with other 7x57s, including a Model 700 in 8x57 as well.
Gunbroker had a Cooper for a while. Nice rifle.