98 Honda Prelude Type SH Timing Belt / distributor o ring?

[Charles]

I just had the timing belt changed on my 98 Prelude, the clutch was also replaced at the same time. Anyway my car has been leaking oil since I got it back. At first we thought it was from the transmission (washer wasn't seated right on the filler bolt) but now my mechanic thinks it is from the distributor o ring. My question is, is this something that could have been cause by the changing of my timing belt? (because it wasn't leaking before) Do you remove the distributor when you change the timing belt? Should have my mechanic checked this for replacement when he changed the timing belt (he replaced camshaft oil seal, rear main oil seal, valve cover gasket and spark plug seals). Anyway now he wants to charge me an additional $130 to replace the o ring and I am wondering if this is something that is partially his fault or responsibility where he doesn't have the right to charge me full price to do something he should have fixed the first time around when he did the timing belt. Thanks!