I'm interested in finding the approximate ship date for a 19-3
Notice that I highlighted your word "approximate." These are just that, approximations. It takes a letter to be certain.
That said, early 8K numbers (up to about 8K20,000) were issued in 1975. Yours could have shipped that year or a year or even two years later. Only the shipping records will tell us for sure.
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Not sure where for about 16 cents a day you will find this much enjoyment and information.