Your local hardware store will probably have some 1/8th foam insulation tape available by the foot. Will probably need to be trimmed to your desired width but that's what I'm doing to eliminate any bg rattle.

I honestly can't speak to what was there originally but I'm sure others can.

I use the Velcro fuzzy side as a replacement.

Ha! I second this! I put it in the same spots as the old foam, works great!

I third this, think I originally got the idea from Pinhead52

The original black foam was made in the devil's workshop and boxes of this evil foam were sent to the Gottlieb factory... This black foam will eventually destroy the paint on a backglass... I always try to get rid of the black foam that touches the middle of the backglass, and then use the Velcro technique on the edges of the backglass... I thought the Gottlieb design of holding the backglass in place with the light board was a weird one...

I can attest to this. The rattle pad messed up what was otherwise a pretty pristine backglass in my JO. I got a new one from Ron Webb due to that.

Remove, use the fuzzy side of velcro as Ken suggested.