2 things I can think of.

1 = '80 ( I think only '80) had factory clear grill marker lights (might only be on fleet models). I found a set in the JY years ago and put them on my '83 and they had Ford markings on them. They also sell them clear aftermarket. I no longer have the '83 but I do have some pics in my gallery.

2 = Someone, a bunch or years ago, told me there were "Night Editions" as well as "Sun" or "Fire" Edition that was all red. Not sure how much truth was in that. They also mentioned it was a 1 or 2 year run.

 

Mine was built in November of '79, and the only confusing thing to me is the early ones tended to use more "prototypes", or in other words, they tried a few things early on then changed them about halfway through the 1980 run. Best example is the factory clocks. Most parts books lists one style for '80-'83 or '84, then another through '86, so I got a clock out of an '82 that is listed as the same as my original. Turns out the 1980 one had a different plug and indeed had a different part number. Halfway through '80 they started using a clock with an '81 part number, which is what's listed in the books.

Then there's the instrument clusters, door locks, door SHELLS, clear turn/park lenses, steering columns, I could keep going...

However, these are all "one-year-wonders" that make owning a 1980 interesting, but there were absolutely no crossovers.