Whats hidden under there?

[southern_boy]

This is on the inside of where the door closes. Not on the door, but on the part that is against the door when its closed. What is hidden under there? because if you look close enough you can see some sort of lettering, and it seems it was painted over, or was it just like that? anyway, what could/is it?

 

[Midlife]

Sheet metal date and foundry stamps. Looks normal.

 

[southern_boy]

Sheet metal date and foundry stamps. Looks normal.

Thanks Midlife, I was just curious because I've seen pictures where the tags on the doors were just painted over leaving it where you cant see any of the lettering on it, so I was wondering if it was some kind of stamp that has some kind of info on it.