Mystery scope mount

[WeedWhacker]

I've been trying to find out what sort of scope mount came with a HADAR II rebuild, and I've had no luck thus far. It seems to be missing the rear ring, but it doesn't have a rail. The base seems to be "permanently" mounted to the cover, as there is something akin to solder keeping the screws affixed on the underside.

Has anyone seen one of these types before? If so, what type of part/ring do I need to complete it?

 

[WeedWhacker]

Mystery solved: it is a Leupold STD one-piece mount with 'high' 1" rings. Got the parts I needed to complete it in and it works great!