Getting closer. It appears you have a single speed windshield wiper, and your question is are the grommets used to go thru the fire wall a different diameter between the single speed and two speed systems. The only info I can supply is the hole and grommet is 3/4 inch for the two speed system. I would assume (it is Ford, so let the buyer beware) that the hole size would be the same - one less tool on the assembly line. So, your reproduction grommet may be incorrect.
(Whew.)
Do you remember where you got the aftermarket item from?
Jim