Not sure how accurate it is but it looks as if tickets have generated in number order. Last time I looked it was up to around 1600 so by that measure there would be 300 left. Good chance they might allow pay on the day if that's the case but that'll be up to Lincoln.
It is for home fans, can't see a mention whether it is for away fans. Presumably it's dependant on whether we sell the allocation before 12pm. I'd maybe give the box office a call, or Lincoln's box office.