The replacement bolt is an M14x1.5 (or is it x2.0? I forget, whatever the standard is for M14s) 120mm long class 10.9, I forget how long the unthreaded portion of the shank is though. You can pick the bolt up for like five bucks in various MOPAR discount locations (search the forum, there are a few threads listing them) + stores.zmjeeps.com as OEM part number 3420 2118, the nut is OEM part number 1150 2814 on the same sites and costs another few bucks.
EDIT: I know this won't help you this time around, but this is exactly why I buy new hardware for EVERYTHING before even starting - I had new bolts, nuts, and U-bolts+nuts for the whole job on hand before I even started my lift. It gave me a lot more peace of mind and I ended up using all but two nuts (my weldnuts got lucky.)