I converted 2 x 1971 and 2 x 198x Allen keyboards, which were functionally interchangeable with one another, so yours should be similar. I went with converting to 8x8 matrix, which meant rewiring the contacts entirely, but I didn't think it was really that bad a job, as long as you follow good soldering practices and work methodically.
The results are everything I had hoped. I have read elsewhere on this forum that the leaf contacts are "old tech", but I haven't had any keying problems. Everything is nice and adjustable. I used Midi-Hardware's components for MIDIfication, and I understand that Roman incorporates anti-bounce features into his boards, so maybe they would not be as satisfactory with other brands, although those may have similar features, I don't know.
An added bonus to the Allen keyboards is that I came up with a way of adding tracker-touch, using lots of 10mm rare-earth magnets (2 per key), available on eBay. (I can't take complete credit, as I got the idea from another poster to this forum.) If this interests you, I would be glad to post or send details.
If you happen to run into any more of those keyboards beyond what you need, I'd love to get my hands on one more of them. Good luck!