Vintage Bumper 354

Hi there,
I got my hands on this Omega watch - I did not pay a lot and just fell in love with the look (each to there own) it also is the first Omega watch I got...
Nevertheless, now I am a bit curious about the exact model and have a few questions about it, I would like to ask you guys!

I guess the watch was badly restored and repainted, looking at the dail (the six is not in the middle... and so on)
Also, the crown is not Omega as the sign is missing, I guess.
And the bracelet is some cheap exchange.

Anyway, I am more curious about the inside and the crystal?

The crystal seems like plastic to me it is not glass anyway, very light, and it has this typical plexiglass feeling it i hit my teeth against it 😉
but the seller says something about mica... probably MICAVER®
Does this make sense? And was this used on these watches originally?

The inside of the watch might be original, but knowing that so much was done here, I just want you to have a look.
It does have that typical "bump" if I turn it and the watch keeps the time, but what year is it? 1952 or later?
Do these ref nr. and othere nr. make sense ?
I don't know what to think about it?

Here are a few pieces of Informationen I got from the seller and the pictures of the watch:

Any information or help is appreciated!
thanks

(I also want to write a feedback to the seller and thats why I need some more information. ) thx

Okay, thank you for that.
The whole sub-second caliber subject... does after all sounds a bit more complicated as I thought and I got to read myself into it - very interesting stuff, how a automatic watch works especially the bumpers.

So nevertheless, you have been a great help on this and I appreciate your answers.
Thanks again