Beats me. Do you have F58 stickers on the bedsides? (I kid, I kid)
Maybe the '89 sales brochure has that type of info? To order this, includes this, or must have that option, type of chart.
Richard
My thoughts, too.
Back in the mid-60's, when you ordered a Chevelle & checked the 'SS' box, that included the F-41 Suspension, bucket seats, gauges, emblems &...
...a BBC (!) 3 different ones.
You could order each of those options separately on a non-SS Chevelle, (Without the emblems, of course.) but once SS was specified, the addition of the parts within the option were pretty well non-negotiable.
But I'd bet that there's a bench seat '66 Chevelle Super Sport unicorn out there somewhere.
If someone knew how to read a sales order sheet or had an 'in' of some kind, there was always a way to get around a basic standard.
RPO-L78 wasn't even mentioned on an order sheet for the '68-'70 Novas. Most salesman didn't know that that option was even available in that vehicle. A person had to know previously about that & then write it in by hand at the bottom of the order sheet.