Is there any distinct difference between the mc16 and mc 18 fuel tanks....if I were to go by the part numbers and corresponding frame numbers ( in the part manual), the part numbers for both appear to overlap ..this means the same tank and frame was used for both bikes(?) and that and mc16 of a late sin. could be using the same tank as a an mc18...is this correct?....here's the short of it ....my mc16 tank looks ..not so good. I have seen both mc16 and mc18 tanks ,that look like the same item ... in very good condition, on the yahoo japan auction sites ...are they interchangeable ?