Sweep lock
Thanks for posting. This looks a bit like the 90-281 Flush Mount Lock to me. The dimensions seem to align with what you report. Please compare and let me know what you think.
The only other lock we sell that may work is our 90-298. This does have the same hole center spacing at 1-5/8", but the backset is 5/8" rather than just 3/8", so it's still not exact.
Those are unfortunately our only two options in this style. I'm very sorry for the inconvenience.
That's fantastic news! Thanks so much for the update, and of course for the business. We really appreciate it.
Please feel free to reach out if we can be of any further assistance.