My 1883 came with the letter. The letter for my 1883 states the stocks are wood and the finish blue!! The only things blue are the top-lever and trigger guard which are niter-blue.
Letter arrived.
Mine has a wood stock also!

The letter does state that the information was "
retrieved from the original Colt shipping records", so not surprised that details are limited.
Grade, weight, gauge and barrel length all match the letter.
Shipped to Detroit, MI, so it didn't travel very far in the following 123 years, (Shipped Feb. 1899) as I purchased it just a few miles northwest of "The D".