I got the link to the above photo from another member, but to date no-one has been able to find this particular vintage SKS mount. Could be a variation on the Russian mount, made by China, Czechloslovakia, Romania, Vietnam, Egypt, or some other former satellite state or strategic/pinko-Commie ******* ally.
My main problem even with these is that the screen-used hero rings had screw thru-holes drilled off-center to the flanges, and not only that, on one side there's no scallop cut to provide clearance for the screw head, meaning the hole would have to be drilled much closer to the flange edge:
The asymmetry and sloppiness of the screw holes is frankly driving me nuts. :confused