It was my understanding that the mudflap was there to offer protection to
the propane tank and valve, therefor only needed on the left.  I've never
seen them on anything but a Westy.  don't know this for a fact, but was told
by an old dealership mechanic.
Steve Sandlin
www.steveslockshop.com
'84 Wolfsburg Westy
'79 Transporter
'00 New Beetle