It's a German-GI 4x Hensholdt. It has a BDC calibrated for standard 7.62mm NATO ball on the right side of the turret, and a "porthole" on the left for a reticle illuminator. After years of searching, I found the little light itself, which was apparently quite rare until a stash of them came onto the market.
Very nice indeed; didn't even know they had illuminated reticles. hmmm. black rifles, gotta luv 'em. Someday, perhaps. That set-up would be quite a hit at the next shoot-moot. :-)