Hello, Sorry been working on one of the Novas and not checking here.
I am not sure there was much to do with the engine on the Fisher side. (Especially on the Sheet that was mainly used just to tell the guys in the soft trim shop what seat to build) The Assembly Manual (which was definitely NOT the gospel) shows the fuel lines and heater box as GMAD installs. However as mentioned above may have been the only reason they were there.
However here is why I do not think they matter: In 1970 they dropped the engine RPO altogether.
I have seen L48, L65, L34 and L78. So in 1969 I would expect to see L89 (if there was one) but not 230, 350, 307. The standard engine like the 307 did not even have an RPO. It was the standard, so why call it out?
The trim level could be different even on SS cars. So They probably called it out anyway. Maybe as a reminder to put in a black steering wheel.
The Fisher records were trashed when absorbed into GMAD. Remember this was a hate - hate relationship. Supposedly some of the design documents are on file with the lawyers in case they were sued. Also much of the hard facts were on computer tape. The records were then compressed, printed, the micro filmed - Like the GM of Canada source microfiche that condenses a whole car down to two lines of RPO codes and a few other numbers of computer type.
That is also why you can not get an exact listing of how many Red L78s with White interior with the special fluid monitor were built. GM summarized production by RPO, printed it out and reused the tapes. There was no hard drive storage as we know it today. no databases, and no thought to go back to see what a car had. It was sold and gone. Any needed information was on the POP or on the car in code. I'd almost kill to have the complete order of run tapes for Willow Run for 68-70. There wouldn't be a thing you could not know about a car with the information those tapes contained. However they were probably reused within the week.
That is why my pet project is to catalog as much as I can to statistically show the Normative Practice. A great term stolen for the CRG by the way. Who is doing the the same for the first gen Camaro. The only difference is guys seem to be throwing data at them.
Greg