Other than tossing the belts (which it probably did), the only possible damage might be the front oil seal, which seals on the balancer hub surface. It's cheap and should be replaced anytime the balancer is removed. GM part #12585673.
The bolt may have scarred the steering rack tube when it backed out, take a look at that too.
The ARP bolt gets torqued to 235-240 lbs/ft.
You didn't say what balancer you're getting, but avoid the ASP aluminum unit, which is substantially lighter than stock...It's pretty well known to cause timing chain failures from it's inability to dampen harmonics. I used a 25% Powerbond/SLP balancer with good results.
