Outer sheetmetal is all ~same through entire run.
difference is how many and where holes for trim are.
70's rigs have line of holes for stainless trim
'84-'91 have crapload holes for woodgrain.
for example my 1988 has 1965 fenders on it.
I have a lower rear section of a passenger fender and a possibly a driver fender if you're after lower rear patch panels?
Cannot remember if I still have driver fender laying around?