if you don't know how to look at the ports and tell, then look on the underside of the intake, if the part number is 300-7 then its the 273/318 port.
sounds like a pretty good deal. i'd like to have it, but i already have 6 intakes hangin' on the wall including 2 small port street dominators lol. , if it turns out to be a small port, then put that with the ad info, it'll most likely help you sell it quicker. good luck with your sale.