Fuel Pump - Rebuilding one, where does the small foam piece go?

[KM7]

On a Carter fuel pump Casting 0-3000, and P/N (new) 3854053. (old) 0987024.. There was a small piece of foam inside the fuel pump. The guys who sell rebuild kits say it is not really needed but if I can figure out where it goes I will put it back.

Anyone know where it goes?

This is on a 5.8L Ford 1991 motor.

Thank you