There is no first or second generation minis. On release a few were sold which had software issues, this was resolved by offering free board flashing/exchange. The poppet had an issue also, and again this was quickly resolved with a free replacement. It was only a few guns this happened to, and yet people still post away saying "make sure its gen2", which misleads people like yourself.
Ok so my point being, if you buy a mini brand new, it will def be the working one. If you buy a mini 2nd hand, you would be very, very unlucky to find one that hasn't been sorted, or indeed if it needed sorting at all.
If you are the unluckiest man alive, and it comes with any sort of problem, you can PM me, and we can fix it no problem.