Scorch, these guys
http://www.germanguns.com/technical.html list it as crown S for smooth bore, but I checked some of my other references and they have it as black powder. I have to see if I can track down the original German rules.
As for the date, the standard was a month/year stamp, I've not seen any actual date (which excludes that 1436 from being a date mark under German date conventions (it would need to be day/month/year). The number underneath could be a 138 which could be a date stamp, at least by format.