Need for replacing U Bolts when installing new shocks

Having Roadmaster Shocks installed with my disc brake install. Installer indicates that we should replace the U Bolts while having the new shocks installed. Reason the installer indicates to replace the U Bolts: "Any bolt, of any grade, when torqued, stretches. The better the grade, the less the stretch, but none the less, it does. I really have no idea what grade of ubolts these RV manufacturers are using, but my guess is it isn't the top grade. So, when you look at how the whole suspension is designed, there is four u bolts holding that axle, to the springs, to the rest of the rig. They are a very important part. Their strength and integrity are important." He indicates this is a mixed subject where Etrailer will say you can use the old Ubolts and other manufacturers say you should not.

So what do you all think and what is your experience on this? Having the disc brakes installed today and didn't find out until last night that the U Bolts were an issue. The Roadmaster dealer did not send them as part of the package. Guess if new U Bolts are required, I will have to try and locate somewhere in the local area to find them or delay the install of the shocks.

Really appreciate any comments you may have.

We had new U-bolts and hardware when our entire suspension was replaced a few weeks ago. Everything else is new, so we didn't have any problem with the new hardware used.

While bolts stretch under load most bolts to not exceed the point that they cannot return to their original length when the load is removed. The exception is if they were designed to do this ( torque to yield ) of they were over torqued. I think some one is trying to sell you something that you do not need.

Any heavy duty truck/ trailer repair facility in your area should have the appropriate stock. ...Ubolts for RV are not anything specific to the industry.

Installers found them locally. Great news. Predicted to have rain, thunderstorms and winds 20-30 mph this afternoon so majority of install will happen tomorrow when the weather tames. Thanks for your inputs.