Looks like a full plate camera with reduction frames for smaller sizes.
Wow what a beauty ! And what a find !
Cleaning up the lens can be tricky, a repairman has to hold it in his hands and see for him self you give you any idea of what is wrong with it and what can be done about it and the cost involved.

The Dallmeyer is a very desirable lens.

If you can have it cleaned I would building a modern back for it aswell and keep all the original pieces.
In that way you can photograph with it and still retain it value.