Not an expert on the Camaro, perhaps forum members can compare with their cases. Heuer did make private label watches of most of their iconic pieces, including the Autavia, Camaro, Monaco, Camaro, etc. for Dugena, Clebar, Benrus and others. Some argue Heuer didn't in fact make at least some of these but that they were made by other companies with many of the same parts. So perhaps this is an unmarked private label case that has been
Heuerized in which case I would try to recover my money. However maybe there are confirmed examples of the Camaro that have the same caseback and similar use of case number and case back engraving as your watch. The lugs are in fact different, however a couple of weeks ago I had a 1163 Siffert and Viceroy in my hands and the cases were also slightly different, most notably the lugs, although these hadn't been polished. The deeper you dig in vintage Heuer, the merkier it gets.