U-Bolts: To re-use or not?

as above...properly torqued to 45 lbs would not distort the metal to a fatique or damaging level.
...now if they are not the original installed pieces,who knows what the last guy did? Just look at
your removed parts and if the threads are messed up or rusted badly, replace them.
Check them after a few miles if you re-use them.