Heat Shield Part Number?

[TM]

Can someone tell me what the part number is for the heat shield
under the body of a 1991 200 quattro 20v? The specific part I'm
looking for goes across the middle of the underbelly of the car,
about 8 inches wide and maybe 2 feet across, right over the center
support bearing for the driveshaft. This part broke off recently,
for some reason, and I'd like to replace it.

The part number I have is reported by the dealership to be not
on file, so I need to find the correct number somehow or if there
has been a supercession.

Otherwise, being aluminum, I'm sure I can just get some sheet
aluminum and use some tin snips to basically fabricate my own
heat shield.

Taka