I know very little about GP's, might say nothing, but I always find it interesting when there is some kind of discrepancy in numbers or mystery to be solved. I had to do some digging after reading your reply to Richard. I found an article by J.R Hobbs from July 98 issue of GM. The article is a little confusing and there are a couple of typo's here and there but what comes out in the wash is that 223803-224056 were indeed 1930 models still in inventory into the 31 model year. I'm guessing you know this Chris, from what you said about yours? He said this group of 5 3/4" bore tractors were rebuilt into 6" bores (not to be confused with the crossovers) in Jan and Feb 1931 and that they are listed as 1931 model tractors in the serial number register. This would account for yours being "recorded" as being warehoused on 2/6/31 even though the tractor had originally been built in late 1930. Makes me wonder what the original handwritten register said about them in 1930? He went on to say that one telling feature of these "converted" tractors, which were for all practical purposes just like a 31 model, was that they retained the C300R maincase. So I would assume yours would have this maincase and Richard's would have the C1733R maincase? He also states that the true beginning serial number for 1931 is 224100 (leaving out 223803-224056), not the numbers listed by this website or T-C Club, and that tractor being built on 12/18/30.
Quite a story!!!
Did you know all of this about your tractor?
Sorry Richard, I don't know anything about your tractor other than the build date probably is correct and I would completely agree with what others have said that it may have to do with some updates. Probably is or was some record of it somewhere. Probably the dealer that did the work or possibly even a branch house, but also likely long lost.
I too would be interested in seeing a good pic of the tag. A pic of the tag and or maincase number on Chris' tractor would be interesting to me as well.
Love the details.