Welcome to Autopia. Yes, 303 can be used on finished/coated leather. 303 is more of a conditioner/UV protectant than a cleaner, however, if you maintain your leather on a regular basis you might be able to get away with just the 303. It all depends. Here's a link to their website if you have not already looked.
303 works great on coated leather. Most leather in autos these days is coated. Just make sure when you apply 303, to wipe it on wet, and then wipe completely dry with a clean MF.
