Format should be AAAnnnn 3 alpha characters followed by 4 digits. If you only have 2 digits, seller is probably masking last 2 digits - not that uncommon.
Best guess TAT 1985/86, TBN 1988, though a triple alpha prefix may bridge several years (I have 2 VJP prefix with S/N 16 digits apart that SW dates 11 years apart - was told they make frames and serialize, but may not assemble immediately depending on demand).
As for dates, sent complete s/n to SW and they should be able to give you "Manufacture Date".
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But On 2 occasions, I got 2 different dates years apart - turned out both pistols went back to SW for retrofit (early 4516) or modification (early 3904) and later date was rework date.