Damper spacers for serpentine belts?

[Stang_ROTY]

I checked the side of the damper and I found a part#. I checked my 2000 FRPP catalogue and the part# matched up with a 302 damper. But out of 9 dampers offered (applications ranging from 302 to 460)it was the heaviest damper out of them all. Weighed 12lbs and there is a note saying "The damper has a removable weight that allows use as a neutral balance unit for internally balanced cranks. 94-98Mustangs and Explorer require mods". I hope it aligns up correct. If not, I'll need a spacer.