Rolex - help identifying movement

[PMC]

Hello all

I bought this Rolex Submariner around 15 years ago (I know it shouldn't have an open back, but at the time reps were different ). Would anyone know which movement is this one I'm sending the pic below?

Hope I'm doing this post ok, just started in the forum

 

[SL1234]

That's a 2813 movement.

 

[PMC]

That's a 2813 movement.

Thanks for the info!