Omega Seamaster 166.0216 or 366.0848

Hi, I recently bought this Seamaster from 1970s with 1020 caliber movement (ref number in subject line above), and wondering what you think of my purchase:

- I paid $400, knowing that I'll also have to spend a few hundred to service it as well.
- Movement looked like in great condition
- I am not sure if I found the serial number -- I see a number on the movement that says 871759, but not sure if that's the right number. Maybe I'm looking in wrong place?

I think I paid a fair price, but wondering if you all can tell me anything else about this.

The watch looks like a ref. 166.0216 / 366.0848 and correct. It's from the late 70s or early 80s.

Case and bracelet are not in the best condition (overpolished).

The movement # you mention can't be correct. It should have 8 digits and be anywhere in the 40 mio. range.

I am looking for the same reference, 166.0216 with a reasonable price, do you know where can I look for? thank you in advance