That solves the puzzle. Couldn't extract anything better from the logo and just saw a similarity (frame) with ETA. It is always difficult when you just have the images from the seller and not the watch in front of you.It's actually not an ETA movement, it's by Durowe in their time in the ESA (hence the shield-like logo) as Intex - so there should be an INT inside the shield. The movement is something like the Durowe Cal. 451:
bidfun-db Archiv: Uhrwerke: Durowe 451 (INT)
German makers (PUW also) sometimes liked to put the beat rate on the movement as well so the number you see should read "21600" (as in A/h).
Better don't trust it too much, at least if it is not confirmed by a garantee and a return privilege. Then you can have it checked by a watchmaker, and return it or negotiate a price reduction, if the service turns out as some drops of oil on the back side.Seller claims the watch has been recently serviced.