IWC vintage Real or Fake? Help me buy safe

I would say that it's more like late 1970's to early 1980's.

That seller has been around for a very long time. They are usually on the expensive side, but they have a nice inventory and a lot of things you can never find anywhere else.

Not sure there is a huge collector value to something like this, but if you like it and price is reasonable, should be a very nice watch.
gatorcpa

582.379 is a number that shows up in several IWC cases in this period, the ones that have a "bayonet closure" (you can see the arrow with the script "OPEN" on the back of these). It's a patent number, but often quoted as a reference number because it is prominent inside the caseback.

The correct reference number should be 3077 according to the following data sheet - it's a quartz watch using cal. 2405 (which is an ETA 940.111 that has been finished by IWC to their standard). Going by the serial number inside the caseback, the watch (case) was produced in 1978 or 1979.

I'm not sure but this might be the enamelled dial version (the black dial version also shows roman numerals instead of stick indices).