how do i know if i have a mopar performance distributor

Best if you explain more about what you are looking for.

I have three I bought new. Green tag on one - the Chrysler built version. Mallory built version is externally identified by the metal (vs. plastic) retaining collar on the lower shaft. Removing the cap and rotor, the top of the hollow shaft the rotor seats on is brass colored. Prestolite based version was intended for racing. Externally the housing is aluminum but has the cap notches are for the prestolite cap, it has a mechanical tach drive, and no vacuum advance.

Internally, all of them came with one light primary spring and a long looped, heavy secondary spring. Although MP sold packages with two very very light springs, the distributors themselves that I have did not come that way. The super heavy secondary springs (especially on the tach drive dizzy) is to offset the slew rate of the ECU and any mechanical retard at high rpm (4000-8000 rpm).