Not sure it's a mistake or they chose to look the other way:
Quite a few vintage Longines conquest non power reserve came with cal 294 bridge on a cal 291 movement...
(The only difference between 291 and 294 is P.r.). So they were P.r. movements with the P.r. part stripped away.
Similar with Rolex with the 1570/75 movement (no date/date)
Click to expand...