No. Ruger did make at least one prototype of a Mini-14 type rifle in .308, but it never went into production. I do not believe that it had the Integral Scope Mount.
Yes, the rifle you refer to was to be called the XGI, and was a sort of scaled up mini-14 to be chambered in .308 and .243 Win. It never produced any kind of accuracy, maybe due to a gas system problem, so was never marketed. I can't believe it could have been WORSE than the Mini-14/30 in regards to accuracy/consistency, but must have been!! (TOTALLY unacceptable)!!