I hope this is the right place for it,but how can I tell If I'm getting a JDM rear bumper or a USDM bumper with the molding?

 

The JDM bumper support is only a mounting braket with no real support. The EF9 bumper has a slightly rounder shape, the exhaust opening is slightly larger. The only real way to tell is that the usdm bumper for 88-91 is all black on top and the molding has no separation line on the top of the molding were the jdm one does