Shock absorber kits question

[Scotty59]

I want to put shock absorber kits on my travel trailer but I have one question which I'm curious about the upper brackets that you self tapping bolts through the frame to mount them does this week in the frame and anyway I have a Lippert I beam type frame

 

[packnrat]

i would not trust screws.
bolts ok ( if at least grade 8, and 9/16 min dia.X4)
weld is best.

but any holes in numbers for a small area is not so good. but should not cause a fail. can not say as to your exact frame.