Just saw this thread or would have thrown in my 2 cents earlier. COPO as stated earlier was a Chevrolet thing and had to do with how the cars were ordered from the factory. Olds, Buick, Pontiac, and Cadillac all had their own sales and marketing teams as well as their own engineering release systems for Production. Central Office at that time was only for Chevrolet as far as the car divisons go. So the COPO would naturally only apply to Chevrolet.
The 4 divisions all ran like separate businesses and the only commonality was at the BOP plants where more than one brand was assembled. That later became GMAD when the gov't was looking to bust up GM. At that time half of the new cars sold was a GM, half of those were Chevrolets. Chevrolet Engineering was in the GM Tech Center, whereas the other divisions were not located there and ran independently of that.
Olds had two ways to get a car built on the assembly lines. Either a production release or an engineering release. Engineering releases were never for salable cars. They were for preproduction units or experimental purposes only. A good example would be the 2 swiss cheese frame W31's that were built there in 1970. At least partially built. They wee pulled off the line at Body drop and pushed out the back door into an enclosed trailer and never heard of again.
Engineering garage did a lot of the modifications to production cars after they were built. If these cars were built to the production release process initially, they could be converted back to production level and resold. Not all got totally converted back if you had the right connections. It would have to be something really invisible, though and the modifications that were put on the car while technically an engineering test car would and could never be on a window sticker.
No W30 wagons built on line. Indy pace cars (actual ones at Indy) had all kinds of tweaks done at Exprerimental garage. And if Dale Smith had anything to do with it, all bets are off. They did everything imaginable out there through his "back door" connection.
