All the original PNs for the various bolts and stuff are no longer made, and tracing down the bizarro JIS Toyota bolts elsewhere has proven quite difficult. Of course I could throw on regular metric bolts, but in case any one else wants to do this, here are the specs of replacement bolts that are still available:
It turns out the stud is still available,
Bolt Stud - Toyota (90116-12005) for about $2 list.
An interchange for a M12x1.75x32mm long bolt is 91212-51232 for about $3.40 list.
If you go the dealer route, add in two lock washers (one for the bolt, one for the stud) part no. 94512-01200 and one nut for the stud, 94115-41200.
It would be nice if you reported back to @Coolerman the specifics on the stud.