Maybe there should be. There are registries for all kinds of unique cars. This is one of those examples where networking would come in handy if you needed something for a Challenger/Sapporo. I'd like to suggest it to DSM, but I doubt he'll be back. I probably wouldn't.
Their import is certainly documented somewhere. The number of them registered could be another matter. In Germany, all registries are documented and even made public. This one is unfortunately documented according to brand and not fine tuned according to individual model. Although, maybe through extensive digging, a list might be published according to what's exactly available there: https://www.kba.de/SharedDocs/Press...tand_01_18_pdf.pdf?__blob=publicationFile&v=9
