It's a Neiman lock, so the original key would have been stamped Neiman.
https://www.stein-dinse.biz/images/product_images/popup_images/28782550.jpg
I sent the PO the photo and other responses and he found two more keys that he is sending to me.
He said "Phil, I think I have two more keys, I will send them to you. W. Germany, Newman"
The cut on the shorter one looks like the Ignition key I have, so the other one may be the fork lock key.

Did original keys have any sort of Guzzi logo on them?
EDIT: the keys came today and the one that looked like the ignition key with a similar cut does not fit in the ignition - it is a little fatter than the one that works. The one I thought might be the fork lock key slips into the fork lock easily but does not turn. I am soaking the lock cylinder with penetrating oil to see if that helps.
The PO also had a BMW that he recently sold so these keys may have been spares for the Beemer. The one that I thought might be a fork lock key has Neiman on one side and "W.-Germany" on the other and looks like an original key rather than a copy.