I bought an after market fuel filter for the JDM a few weeks ago, didn't pay much attention to it tbh, but will go and check what type of fitting it has and let you know. (I'm sure Pushki's right though - and hex bar stock is bound to be cheaper than square bar stock, so it would make sense that's why they've used it on the pattern part)
ps the Honda one also has indentations on the body above the flange. Do I win the spot the difference contest?
i would have thought the indentations above the flange are of no use due to the cage. the filter sits in grooves and bottoms out when it hits the flange.