I'm no expert on the rubi, but here's what I found on the web.

Looks like you'll need a compressor.

The other minor thing is that the air compressors (2 - one for each locker) are low pressure units and cant be used for anything other than the lockers.  

But can you upgrade to one good compressor with minimum mod to the stock systems lines and wiring.  

The factory Rubicon compressor only makes about 4-5 psi. If you run more than that to the lockers you'll blow 'em.

I suspect you could run a regulator off of a standard compressor but I imagine the regulator will cost around the same as a Rubicon junkyard pump. I'd go with the pump.