I'm seriously amazed by some of the comments here..
Please take a look again at the pics provided by OP and the other comparison pictures in this thread. The numbers merely resemble the refined stamping we see on the other pictures plus some of them resemble more of a blob than an actual stamping... what's with the last number? Supposed to be a 2 I guess? What do you think happened here? The stamping machine at Lemania/Omega had a bad day? A few to many drinks the night before? Someone at omega restamped this part by hand? And then there are the drilled out numbers...
I'm not jumping on the conclusion that the watch was maybe stolen, as therefore I would believe someone would drill all the numbers clear out.
But this part of the movement has at least been tempered with and therefore the watch for me would be a no go except if I wanted to strip it for parts.
It's a shame as the dial is wonderfull, case seems sharp and 220 bezel is a nice plus, but I think OP did good with returning the watch.