well, it might be an aftermarket thing, but a dealer installed radio would still be a "GM" radio - Bendix was/is actually the Bendix Aviation and Radio Company [or something like that], and were the first to introduce solid-state auto radios, so may be why found in yer GM, as also in other makes - at least some TF radios were made by RCA - many 'accessory' items were shopped out to suppliers, and I don't think any radios would be labeled as 'made by GM', but some are by Delco - what makes it a GM radio is just the fact that it was made to GM's specs to fit yer dash - date of manufacture is appropriate for a 66
Bill
