Interesting Colt factory letter

I recently lettered a large quantity of Colts and got several neat hits back in the process. This one was especially gratifying because it was totally unexpected...and it turned out being free.

The pistol, itself, is neat. It's pictured in Meadows' Volume I and is believed to have been assembled from parts because the serial number is in the range listed as Receiver Only in the Colt shipping records.

It has a slide that many consider to be likely manufactured by Savage, but no one knows for sure.
https://www.milsurps.com/images/impo...12/nb1mt-1.jpg
https://www.milsurps.com/images/impo.../2rm757k-1.jpg
https://www.milsurps.com/images/impo.../11jupvc-1.jpg

Neat letter!