Looks almost like a converted pocket watch

 

I think you're going to have to find a watchmaker, have it opened, and write down all the numbers and details on the inside of the caseback. If you can get serial numbers, Omega has a very good online vintage watch database that could help you find further information.

 

I've seen this a fair bit, there was a guy selling a Patek Philippe authentic 47mm wristwatch not too long ago (think I linked it to Trev at the time). It was a genuine Patek pocket watch, turned sideways, with a secondary case and lugs attached to it, and a 22mm strap. Because they'd turned it sideways, the dial had been refinished with the Patek logo reprinted 90 degrees to the left, and the seconds subdial was at 9:00 o'clock.

All in all, a very bad thing to do to a Patek. In this case they've not rotated it but you can still see what it was originally.

 

Could you post a photo?

Those don't really sound like something you'd find on an Omega.

I'd do a bit of research, because right now, as an Omega watch, its worth basically very little. I mean if you went to a pawnbroker you'd probably get under $100.

However. To a military memorabilia collector, it could be interesting. The inscription "C/O MIS, 27/4/59" I'm guessing could mean Commanding Officer M.I.S. from 27th April 1959.

Now that becomes rather interesting. There was an organization in Poland called the Military Internal Service, that existed from 1957 to the 1990s (during the communist era) that were a sort of secret police (read more here: http://en.wikipedia.org/wiki/Internal_Military_Service)

Now the other numbers could be service number, or serial number, you never know, if it was a commanding officer, it could have been someone of some importance in Poland.

Now if this is the case, that would take it from a ruined Omega pocket watch that has modest value even in original condition, to a cold war curiosity of significance to collectors of militaria and history. This, coupled with the fact that he may have worn it in its present configuration MAY make it worth something more than that, maybe a couple of hundred, maybe more to a collector with an interest in this very narrow field of history.

On the other hand, I could be completely wrong, in which case you're back to square one. I am keen to see the photos of the markings just purely out of interest, and I hope this is of some help or direction, maybe if it actually WAS a Polish M.I.S. commanding officer that owned it you can find out who, and attach a name to it, and maybe see if that person ever did anything interesting in World War II or in Polish politics. That's where I'd go with this.

As it is, trying to sell it will get you about nothing, and its better to just had it on to a family member or keep it as a conversation piece though.