I'd leave it alone for this batch. Inspect the large O-Ring when you clean the keg and then decide. You could do a test run with no brew in the keg, with a small amount of lube, to see how it acts. Put some StarSan solution in there, so that it's ready for the next batch.
BTW, while I'm filling my kegs, I put the keg lid (O-Ring included) into the bucket of StarSan. Not only does that ensure nothing hitches a ride, it also gets it wet for when I close the keg and put it onto gas.
For the other O-Rings, I usually try the QD on the posts before applying any lube. If it goes on easy, then I leave it alone. If it seems to have too much resistance, I put some lube on it. YMMV