I'll send them an email now asking how much they have in stock.
Great! Maybe we could even get a little discount if we buy a considerable amount of arrow keys
On the other hand:
Now that a TKL set is confirmed, do you really think the vast majority wouldn't be in favor of adding those 4 arrow keys and increase the cost of the set like 3-4$?
I mean 8,50$ feels kinda expensive if you consider that ALL the other keys cost 42$...