Well, I guess I will add to the confusion....(yours and mine)....
I went to that "other" website to take a look at the parts manuals.
78 Intruder and Invader used aluminum rail part # 39105-3501. Same part # for both sides....meaning there had to be no offset??
79 Intruder and Invader used 2 of part # 39105-3502. I suppose the new # was for the change from the 78's using the threaded eyebolt adjuster for the front spring and the 79's changed to the cam shaped thingie...?? The cam required a couple more holes drilled in the rail for attachment??
The 80 models get really weird...
The Invader calls for 2 of rail # 39105-3507 (identical with no offset??)
The Intruder shows using 2 different rails, a left and a right with part suffix -3508 and -3509....had to be offset??
The 81 Invader doesn't count because it changed to the newer Vari-Ride skid, but the 81 Intruder shows the same 2 rails (offset??) as the 80 model.
So...I took a look at the track part #'s:
All of the 78 and 79 models came with track # 39125-3502. The original steel bar track that was recalled??
Someone has hand written in a new track #.....39125-3511 in those 2 parts manuals. I assume this was the replacement track during the recall??
Again, the 80 models are a bit weird....the Invader calls for track # 39125-3505. The Intruder calls for 39125-3512 (as does the 81 Intruder).
I dunno.....I think I need another coffee....