Nice. And we weren't too far off with our Nov./Dec. 1943 guesstimate. U.S.M.C. gun seem to have a tendency to ship a bit later than one would expect from the serial; I had one I sold a few months ago which should have shipped in about Nov. 1942, but didn't until April 1943, to the U.S.M.C. at Reading, PA.
PS: If you're interested in what the Maritime Commission was up to during the time when it received your Victory, this pdf. makes interesting, if a bit dry, reading:
http://www.fmc.gov/assets/1/Page/REPORT_TO_CONGRESS_1944.pdf