New here…looking for any help or knowledge on this watch

This watch was passed down to me a few years back. My grandad acquired it many years before that. I’ve not since tried to authenticate it or have it looked at. To his knowledge he thought it was from around the 1930’s.

I replaced the strap (eBay) when I first got it so again unsure if it’s legitimate or not. I’ve tried to research myself but can’t really find anything that matches it, closest I’ve seen is the ‘bumper’

It is in need of service/repair so if anyone has any knowledge on something like this it would be greatly appreciated, before I try and take it somewhere.

This watch appears to me to be either a 28.10 or 30.10 bumper auto. It looks too early to be a 35x series.
These are the early bumper automatics with central sweep seconds. Tip number 1, do not rest the watch
on a sink or any place else where a drop could mean water or hard tile floor. Next tip is to get it serviced by
a recommended watchmaker. In order to get recommendations we really need to know where you're located.