It does seem likely he could be a promotional keyring figure. Searching on eBay.de for "schlüsselanhanger" or "werbefigur" brought up many klickies I hadn't seen before, mostly well-known ones with additional printing, but not this one. I also tried using Google Images to find a match to the design on the klicky's chest, but no luck there either.
The mystery will be solved one day!