Sorry to hijak this thread. I picked this up from an Adv ad for my R80ST.
Pic 1: note shape is like R80ST, not R80G/S, not R65
Pic 2: note filler drain and vapor vent tubes. Also, welded on tabs that have no purpose on an ST or G/S
Pic 3: note ST, R65 style filler but with PITA spring loaded flap like later GS. Also note original color - looks like G/S blue.
Clueless in Pittsburgh