Hi Stefan and welcome to THL.
Don't know much about this reference but I can tell, the watch is good, correct and coeval (dial, case, crown and anything else I can see through the pictures available in the site, whose name is reported in the image you've posted).
Can't see the movement but it surely is a 1121 (K1121 perhaps, which means gyromax, that is a plus). Simply the movement is worth that price.
Of course you'll have to check case and movement conditions and consider, if you care, some other issues, like strap and buckle which are not original.
In short, if you like the watch, go for it.
By the way, it's always a good thing when the seller doesn't know what's in his hands