Earliest 12C Serial Number

[Ron Ross]

You have a good probability, however these calculators are very, very durable ie out of the first 100 Hp 12c calculators sold, the 12c would land on an office desk (vs an Hp 11c might see the horrors of the real world). So the Hp 12c's would see a sheltered life and may have been show candy as well ie sits on desk with very little actual use. So of the first 100 Hp 12c's, 60% might still be working great and are being passed down to younger heirs, just like yours. Where the difference is, you recognized a quality tool, vs a lot of people might have just figured they got Dad's old $10 junk that he should have replaced years ago.