Apparently, whichever mint it was that made these coins (?) made a few in other precious metals besides silver. And I mean "few" fairly literally;
this website has a palladium version of the Germany coin (KM 17), also slabbed by NGC, and reports a mintage of 7. Presumably they struck them to order. I could assume the gold mintage was higher, but probably no more than 100. The "G" in front of the "$5" on the slab in this thread presumably indicates it is indeed a gold version, as the slab on the page I just linked to has "PD$5".
I do find it odd that NGC would slab a coin not listed in any of the Krause catalogues. I can only assume that whoever sent them in to NGC sent them in original mint packaging, and NGC simply took the mint at their word.
As for value, well, for a piece with virtually no supply or demand, no history of sales and no catalogue price, I suspect value is highly unpredictable. Your guess is as good as anyone else's. I assume it's an ounce of gold, so you've at least got that. The sales website for the palladium one has it listed at $3300, which is about four times it's bullion value.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis