Considering a 3590.50

The movement number is engraved on the lug of the watch (it looks like 48,28x,xxx from the photo?). The type of movement (861 vs. 1861) does not add or subtract value. What matters is that the movement number inside the watch matches the movement number on the lug and the movement is in good shape. The watch you are looking at is from the earlier end of the 3590.50 production, sometime in the early 90s.

It's always important to see the movement to confirm the serial and also to make sure that it looks relatively clean... ie screw heads not beat up, no signs of water ingress, paperclips etc. If you cannot get a picture of the movement before buying you will need to have it opened up immediately after receipt and be sure that the seller would take the watch back if the movement is not as advertised.

With the condition of the watch - I would be surprised if the movement was not in good shape. But always important to verify.

The MWO book has some great discussion on the movements. The 861 movement was transitioning from 17 jewels to 18 jewels in the timeframe that is in the vicinity of the serial number of the watch you posted. My personal 3590.50 (with 48,27x,xxx serial number) actually says "Seventeen jewels" on the bridge but has the eighteenth jewel present. MWO discusses this as well.