But, Beware of the Numbers Game...
Long have I counseled against trying to make serial numbers mean anything. But the other day even I got lulled into trying to date a machine via its number.
In the estimable Grace Rogers Cooper book on American machines, published by the Smithsonian Institution, the lists of serial numbers for years of production are given for various manufacturers in the cases that these were available to the author from the manufacturer's original records.
Sounds pretty authoritative? Not on your life.
I checked out a very early W&G against this list and found that according to its number the machine was produced in 1863 - the sixth year of production.
Rather pleased with this, I communicated the information to Maggie Snell who thought for a moment, put her head on one side and said: "Oh, but why then does the machine have an 1865 patent date on it?".
Could it be that the stitch plate had been replaced. Unlikely, for it was silver plated as were other fittings on the machine.
There was only one answer - make no assumption based on a number, unless it's for a front door, a telephone or a premium bond!