The wear does not look that unusual to me, but that may just indicate that I am easily fooled. However, if you were going to fabricate a red-dot by drilling the hole, it seems like the last thing you'd want to do would be to draw attention to the area by adding fake wear. The unit does have the serial number label in the correct place between the two lower feet. According to A Guide to HP Handheld Calculators and Computers by W. A. C. Mier-Jedrzejowicz, the serial number label was moved into the battery compartment when the first version 2 (non-red-dot) units were produced. The format of the serial number itself also looks authentic, i.e. the 5 numbers after the printed "1143A" appear to be stamped on in figures about 1 mm high, and the first number looks like a 0. The back label with the instructions appears undamaged, but I do not believe that it is the label that originally came on the unit. As near as I have been able to determine, the original back label on red-dot units (and on at least some version 2 units, mine included) say "HP-35 INSTRUCTIONS" on top, not “HEWLETT*PACKARD HP-35 INSTRUCTIONS”, and
MADE IN USA PATENT PENDING 3.75 V 500 MW
is not shown on the bottom of the original label. That doesn’t mean that I think this particular unit is a fake, however. I think it just means that it was sent back to the factory to fix the bugs, and HP replaced the original label with a new one of the latter style.
Regarding the auction and why it ended early, perhaps the seller figured out that the unit was special and took it off to re-list it with a better description (and a higher starting bid). Of course, it is possible that somebody offered him/her $100 for the unit and he/she accepted, not knowing the true value.
