If you email Weaver's tech folks w/ the hole spacing and reciever diameter, they can tell you what top mount bases will fit IF...I say IF it was D&T'ed for Weaver top mount bases to begin with.
However, if it's D&Ted across the top, then knowing the receiver diameter can still fix you up. They can give you the part # for a base that will fit the receiver profile. You may have to drill a hole of two in the alumium base to match the receiver hole pattern.
Any man that can lay out lines can do this job easily. A drill press is best, but it can be done w/ a hand drill & vice.
All you need is a bit a few thousands bigger then the screw shank, a bit big enough to countersink for the screw head, a calipers, straight edge, centerpunch and hammer, and a way to drill.