Help identifying vintage Oyster

[Santangelo]

Hey everyone!

Brand new here- family just discovered my grandfather’s old Rolex… we know nothing about it, besides he allegedly bought it when in the service in the 40s.

Curiously, not seeing a model number on top, but the serial checks out to a mid 40s piece.

Any info regarding model, etc would be greatly appreciated.. thanks everyone!

[psion25]

If the model ref is not between the lugs you could also see it in the inner caseback. The dial may have been repainted in the past, i think it should read as "shock resisting".