Hi, thanks, would be interested in how do you know if it was added or not, does the engine code cover it, did the 396 even have the air option, anything special to wonder about a California car with the option. I don't know if the cowl tag would indicate air.
Hi Bob. Let's start with the first question - how do you know if it was added or not.
There were two versions of the A/C system in 1968. The FACTORY installed A/C (called the "Four Season") and the DEALER installed A/C (called the "All Weather"). Factory installed A/C is easy to distinguish because there's a large box known as a "suitcase" attached to the firewall (see the picture below - that big box sticking out from the firewall - and although that's a small block "suitcase", the big block is similar) and the dash control will indicate A/C. The dealer installed A/C is basically an "add-on" system that was placed under the dash. (See the examples below for the "Four Season" - top - and the "All Weather" - bottom - from the 1967 Chevy-II below, but the 1968 was basically the same)
And yes, while the factory A/C can be added by a prior owner to make it appears to be "factory", it's such a major pain that it's really not worth it. However, there are subtle differences that can indicate if it's been added or not but I won't get into those now.
The engine code won't indicate if the car came with A/C or not so that's of no help, but post a picture of the engine suffix code on the front pad and we can probably tell you more about the car in general.
A/C was available on any 68 Camaro (except the Z28 and L78) from both factories.
The cowl tag on the 68 doesn't indicate A/C.
Ed