I just scored a hi lift for free from the old man's garage. He hasn't used it in about 10 years. After I got it all cleaned up and working good, I am lookin to mount it. Since I didn't pay anything for the jack, I am gonna mount it for cheep. I plan to get some 3" bolts, nuts washers, etc. The plan is to run the bolts through the stock rear bumper with a lock washer and nut, tighten it down and then slide the jack over the exposed bolt ends with another washer and nut on the outside.

My question is should I get a backing plate to put behind the stock bumper before I put the thing together?