Yeah-292. I have 2 of the nicer, cast mounts. I know one came off a 292 for certain and they are identical. One of those is holding the alt on in the picture. The loose one in my other picture seems very much more industrial, bordering on home-made, and it puts the alt maybe a big eighth farther forward.
It came in the big box of parts that came with the basket case 292 I bought. I don't mind fabbing my own mounts, but I would prefer to stock stuff if it's available.