The only real date is the shipping date. You then know when it shipped but rarely when it was built. Taking the Model 1955, if it shipped in 1955, you know when it was built. If it shipped in February of 1956, you know when it shipped but not when it was built.

Were models always built in sequence? Unfortunately, no. Often ranges of serial numbers were built out of sequence. Witness the Model 1917. Many thousands were built after WWII but on frames manufactured in 1917 and 1918.

It falls to the searcher to declare his/her parameters and conduct the search according to those guidelines.

Unless and until, the Historical Society or Dr Jinks weighs in with an opinion. Then, at least we will have clearer guidance.

Kevin

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Unshared knowledge is wasted.