Hi Bob,
Thanks, that one is out of the ordinary (-:
H12 is easy, the frame was made December 1941.
G53878 is the 'actual' serial number, when the bike was built up, around April/May 1942.
This is an odd period for bike manufacture and especially for Westfield. Pearl Harbor occurred in Dec 41, and industry in the US started to go onto a war footing. Bike manufacture for civilians was suspended for a time from 3rd April 42, with sales to government agencies only from 13th May 42, and rationed civilian sales from 15th May1942.
Westfield were already fully involved in the war effort. Between February and March 42 they were building G519 military bikes, and this serial number comes after that big block of G519.
So, at a guess, the frame was made around Pearl Harbor, but put to one side for some months whilst Westfield worked through a Military contract. It was then built up as the contract ended, either just before, or just after the freeze on bicycle sales.
So, where does that leave the G3057 number? I'm not sure. You can find two numbers stamped on some Bluebird bicycles (see N131994, B10 (Oct 1935), later restamped A191718 for late 1936). I have guessed that these were unsold/demonstration/display items that were returned for refurbishment and resale. But it is a guess.
For this bike, if G3057 was an earlier serial number, it would be early 1942, which fits with the Dec 41 frame date. So, again a guess, perhaps they started building it up, it was allocated a frame number, then put to one side partially completed to build the military contract. By the time the military contract was finished, new rules said blackout parts were to be fitted, so, since the specification had changed, it was allocated a new number. As a guess, it works.
But for two things.
G3057 would have been an early 1942 number, except that Westfield at this time normally started at 5000, and claim to have started at G17434 in 1942, so this number shouldn't exist as a frame number.
The 3, 7 and possibly the 5 are different font to Westfield's normal font, the 3 being flat topped, in comparison to the usual round topped 3 below it; and the stem of the 7 being a different shape. So I don't think it was stamped by Westfield, although it seems to have original paint over it.
In conclusion, it's interesting, and I wish I knew the answer. Perhaps a Government serial number? (Military bikes have an M stamped in front of the serial to indicate Military). Certainly, I've never seen this before.
Best Regards,
Adrian