The one thing about this bridge that seems to make it different from the Steinberger's and the Kubicki's is that you dont' have to have a body shape that will allow the tuning knobs to protrude past the back of the intrument -- with a little routing for the rollers under the bridgeplate, this could be mounted (and in fact was when I got this) on a P-bass style body.
811952, I'm not sold on this being Kubicki unless they did a radical change of thier bridge pre-'80:
--actual length of the bridge not long enough compared to current Kubicki's.
--the knobs on the bridge above are spaced 2 and 2, where Kubicki's are set euqally apart.
--The bridge saddle where the string rests on a Kubicki is actually one big threaded post that you can twist up and down to give your height action adjustment.
Kubicki was my first guess in all fairness, and I still could be wrong, and would be happy if you did find something to prove it! I just wannd ID this thing -- there are a couple of screws I'm hoping to get replaced, since thier heads are stripped.
--T