Pinion gear questions

[Chris Bamford]

A friend found a looks-like-new 11-tooth pinion and 40-tooth ring gear bagged under the seat of their touring.

There are several markings on the face. The "USA" and "11" are self-explanatory, but what might the other markings indicate?

Also, the keyway is centred (mostly) under a tooth valley, same as on two used pinions I have here, so is presumably correct. Where was the keyway located on that years-ago bad batch of pinion gears I remember reading about on the forum?

Thanks in advance.

[Mark Gregush]

If you moved the key way to under the tooth, the corners would be in the thin spots. Here is something that might help; http://www.mtfca.com/discus/messages/29/33593.html I would say reading that, this one is good.

[Chris Bamford]

Thanks Mark, that makes good sense.