If mounted to the side they would have to be forward of the magazine cut-off. Generally you drilled and tapped the recevier and the base stuck out the left for the Redfield style sights. Could be done both ways.
Based on the original post I believe it is a sporting rifle that we are talking about, so I suspect it would not have a redfield target type base. The OP also mentions a top mounted scope, so that would seem to eliminate the possibility of a top mounted sight base. I am wondering if what the OP is calling a sight mount might actually be some sort of side scope mount that is missing the rings. Photos would be a great help.
John
