While not apropos Colt pistols, here's some comment on markings on S&W M&P revolvers (Victory):
"Broberg's stamp continued to be used after his departure. His initials have been noted on S&W revolvers that were inspected as late as mid-November 1942."
-----Charles Pate, U.S. Handguns of WWII: The Secondary Pistols and Revolvers
I have in my collection an M&P .38/200 Lend-Lease revolver, New Zealand issue, SN V128xxx, W.B. accepted, shipped 26 Oct. 1942.
It's the bottom one.
I would believe that a lot of shuffling was going on at the Colt plant in 42. My USGI 1911, SN 8505xx is "W.B." stamped and with the cross cannon stamp as well. This particular pistol has an "S" stamp overstamped with a "G" in the slide groove which leads me to believe that this pistol was transferred from commercial stock. It does, however, have all the correct military receiver and slide markings. They are interesting to say the least.