I think he tries to keep a list of them since they are considered high dollar cars, that's all. He plays with Chryslers numbers and production figures and the Demons don't fall into that category since they were dealer modified. The 68 M code Dart GSS does however have records and was factory built.
Galen helps people find legit, rare cars and verifies them before purchase or gives his stamp of approval. That I think is his main business these days. At this point I think he has to choose between inspecting a Hemi Cuda for a high dollar client over trying to get $50 from us little guys over a common muscle car question. I'm pretty sure that is where he gets his bad rep from. He's really a good guy and loves all Mopars, but there is only one of him and his services are in demand, only so much time to do this and make a decent living at it, know what I mean? There are other avenues one can pursue to get basic production numbers and tags/sheets decoded that are free, or cheap (Galens books for one) so I don't think he does much of that anymore.
People are all the time wanting to know how many cars of one color, or with a color/engine combo were made. Well, Part of what Galen collects tag info for is to form a database for these options and then try to come up with a fairly close, reasonable assumption based on the information he has. Not all records were kept, or even ever existed for certain things. I hear a lot of people bitching when Galen photographs tags at shows, but this is why. If you don't want your info recorded that's fine, but don't complain when the information you are after about your car doesn't exist. That said, it would make sense to decode that /6 car tag or sheet wouldn't it? But, like I said above, maybe his time is limited. I really don't think he's taking payment for this type of thing and not returning a product.
I'm not calling out anyone specific here, just making random observations about the general attitude towards Galen. If anyone has a specific occurrance of Galen ripping someone off or not returning $$ I'd like to know about it, I'll ask around and see what I can find out.