Early Chronomat bezel screws coming off

[Cimballi]

Hello all,

This is my first posting.

I very recently purchased an A13047 Chronomat and i love it.
As I was cleaning the bezel, two of the small domed screws (not the rider tabs screws) came loose.
I was not able to put them back in pace, since they do not have a real thread.
These appears to be different from the other Chronomat bezel screws I have seen in pictures.
Can anyone tell me how these screws are secured to the bezel?

Cheers from California.