Jim and Gene, Alex put his finger directly on the reason the HHR version of the D4C chip is shown with a "?" in TCR5.
I, too, have seen this chip represented as perfectly legitimate (and in fact, like Gene, I was so convinced that I bought it!). Howard Herz's later comment about the Langworthy manufacturing dates has cast doubt on the authenticity of the chip.
However, the three co-authors of TCR do not consider that comment the final authoritative answer on the matter. We are not completely convinced, for example, that it's impossible that someone other than Langworthy manufactured an HHR rim chip before 1970.
We always hate to slander what might be a perfectly good chip if we cannot be certain. That's one of the reasons we hated to have to write our long explanation about the Borland counterfeits. There is the chance that the good chips from the same casinos will be tarred and feathered with the bad ones, and the entire hobby suffers when that occurs.
For now, we stand by TCR5: in our opinions, the chip is questionable, but not clearly fake.