I know sedans equipped with positraction had a sticker applied to the trunk lid with instructions. Did elco's get a similar sticker, and if so where would it have been applied.
I had a 1971 El Camino that came with a Posi and bucket seats, the label was much closer to the center of the bulkhead, as if the worker who installed it reached between the seats. Easy for him though not aesthetically pleasing.I've heard of them reported in various locations on the back bulkhead from the various plants. This one was near the spare tire. You can just make out what is left of it.
Also seen the posi tag on the drain plug like Greg mentioned. https://www.opgi.com/el-camino/J538...0Ija_nafFqK-FvvNLoX6yhJERja3SZMBoCcTMQAvD_BwE
1969 and earlier Positraction labels are worded "USE POSITRACTION DIFF. LUBRICANT ONLY."
1970 and later Positraction labels are worded "USE LIMITED SLIP DIFF. LUBRICANT ONLY."