[ QUOTE ]
"COPO 9796 and he was very clear that the need for a COPO ended when the 1971 year started with the RPO change."
so..then any car from july 70 and newer had tall spoiler as a regular D80 rpo and not a copo.
You are real close. '71 model year started concurrent with the short UAW Strike that year as 70 production shut down at the end of August. Strike was timed for the '71 roll out on September 14, 1970 as I recall.
Phil