Thanks all for your reply.

I finally contacted R.C.Pace. Nope, not them.

However, I think I solved the mystery of how this rifle came to be. Someone, (likely R.C.P.) "assembled" this rifle in the late 1960's to early 1970's through components from Herters in Waseca, Minn., or they special ordered the rifle direct from Herters with its current configuration. A 1966 Herters catalog shows all the components, and information contained in the catalog indicates that they offer services to build complete rifles.