Vendo 81 model number???

I'm a little confused about my 81's Model/Serial number.  The plate on my machine indicates H81-D & 601-33292.  First why an 'H81' in lieu of a 'V81'?
I read that the first three numbers of the serial number indicate the month and year manufactured?  Mine would indicate January of 1956, but according to some serial number lists I've seen, the serial number indicates 1957??

Thanks, Tom

[Jim]

Hello Tom,

Quote

I read that the first three numbers of the serial number indicate the month and year manufactured?  Mine would indicate January of 1956, but according to some serial number lists I've seen, the serial number indicates 1957??

If my memory serves me, this is correct. I'm not at home to reference any material but are you stating you think there's a conflict between the first three digits indicating the manufacture date and other documentation indicating another production date based on the rest of the serial number...?
As far as the "H", I don't have an answer on that one...
The suffix letter "D" is a version change designation. If my memory serves me, this is the first generation 81's w/ the large coin doors capable of accepting quarters and thus dispensing change to the customer.