Foam pad is listed in the tech as a 'vibration (read noise) damper.'
As said, no use but you won't have one on a pre03 anyway.
Also, if you do it on the floor you might need to remove/drop the arp.
I have done them on a 2post lift without removing it so if you can get both front wheels off the ground by jacking the chassis the arb must drop enough to get it out.
Though for the sake of 4 bolts, if you are doing the job on the deck just drop the bar as it's a bit safer than 2ton of truck balanced above your head