Blake, the small black circular cap on the left side, when looking at it from the rear (look at the photos of the classic that basscat has up) should be your fuel inlet. The vents are square with one facing forward and the other facing rearward. I do not own, never did own a classic, but have owned a P2 and a couple of Cougars. On all of them the round covers have been the fuel inlet. Prior to taking my word for it, or anyone’s word I would open the back compartment lid and track down where that opening goes. If it goes into a fuel tank then you know what it is for. If it is going onto a flexible white hose that drops into that rear compartment then you know it is a vent. On the P2 that I owned the fuel opening was on the side due to the tank being under the seats. That is unless you ordered it with a kicker tank in the rear in which case you would also have a inlet on the back. One way to check for dual tanks is to see if you have a manual valve lever located before your motor . It should have a left, right and off designation on it if you have dual tanks.
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