I would probably replace it for running in the wet, debris, etc as you mentioned. It's probably not critical but...............a wet clutch disc. I know it has a slit in it.
Is it possible to salvage the one you have? Beat it into shape?
I forgot to put mine back on

. I looked and thought it would be difficult but doable with everything assembled. I know the 10mm head bolts are back above the crossmember, but I still think it's possible. gearwrench. I'll try tonight as I'm bored with other things on the car.
I may have an extra one, I'd have to look when I get home. Assuming they're identical.
It is replacable, I do not know a part #
If all else fails......duct tape.
I'm sure in this forum alone you could find a spare. I'm putting mine on and I don't even really DD the car.