Hey 58GMCanuck your right next door to me. I'm in New Brunswick.
What year truck do you have?
Anyhow if your talking about the running board brackets from 47 to 53, short box, they fasten to the frame and underneath the running boards. Also there is a 1/2 round sheetmetal pcs that attaches from the top of the running board to the bottom of the box, also held on by a small bracket. I have some spare running board brackets here, if you need them come & get em.
Send me an e-mail