The Shrock is probably OK, but the mount in the frame rail may have slipped to get that angle.
If you have thick frame stiffeners in the frame horns it tend to help reduce that, but it looks to be a reasonably hard hit.
My Shrock was rear ended many times w/o damage....they're pretty tough.....I think mine's TOTALED several vehicles and severely wounded a few more, when it was on my '01, and, I then swapped it onto my '04 last year. (No hits on the '04 after it was installed though, yet)
Do you have frame stiffeners in the frame horns ?
And, the other guy's insurance can pay for repair to the horns or the Shrock if you do find damage.
Example of Shrock vs Rear Ending:
Lifted Ford F-250 on MT's that totaled itself against Shrock
Picture of Xterra after same accident:
I DID get damage to the rear suspension, exhaust, and hatch, as parts of his rig broke off and flew under and into my truck....I had pieces of his truck hit the INSIDE of my windshield, etc...it was a mess. His steel bumper hit my spare tire pretty squarely.
He was going ~ 20 mph, I was stopped.