Letter came back on the RM today. Guys ask if a letter is worth it. This one shipped with a 5" bbl but has a numbers matching 7.5" bbl. The letter confirms it was done at the factory and the invoice is available from SWHF. As a bonus it was ordered by the Chief of Elgin Illinois PD and shipped to the PD. In this case the letter helped. But even if it didnt it would give me details not available elsewhere and it supports maintaining the history.