Does anyone now the difference between a 22433AA421 and a 22433AA451 coil pack?

Opposed forces shows the 421 for April00-October02 and 451 for July02-July05

I was under the impression that all 2.0 turbo coil packs were the same.


Mach-V lists one part for 02-05 as well.
http://www.fastwrx.com/collections/i...coil-pack-ej20


Any thoughts?

Thanks

Jeff