csj, I just finished installing my cam and having it tuned this past week so this is pretty fresh in my mind. The one thing that I learned through the process is that it doesn't really matter what the specs of the cam are. Now I know I may have to put on the flame suit for that one but from my perspective I could care less what the lift, duration, or overlap are. What was important was how the cam performed in the car. How did it impact drivability, where did it make its power, and how soon did it start to fall off or not fall off up top and was I able to see the dyno graphs of the cam on engines/cars with similar mods to myself.
Now I have no idea what conversations you have had with the shop you are dealing with and whether or not you said I want the car to perform like x, y, and z, if you were shown any dyno graphs depicting what to expect or if you just walked in and the guy said "hey, an LS3 Camaro... use this". I dealt with
East Coast Supercharging in Cream Ridge, NJ for 90% of my parts for the cam swap but most importantly one of their custom grind cams. They tend to take a little heat in the Corvette Forums from time to time over the fact that they do not give out cam specs with the exception of noting duration in the 220's and lift around 580ish. Their cams come in Small N/A, Large N/A, Small Blower, Large Blower, and possibly a couple more. What is more important is they are very up front with dyno graphs to show and prove what the cams are capable of in different applications and based on my current and future goals for the car were able to recommend one for me and then back up that recommendation with dynos on other LS3's with similar mods that they had tuned. When it was all said and done, the car drove exactly how they had described it down low, and performed right on par with all the other dynos they had shown me and I have no idea what the exact specs of the cam are and no desire to know.
I would assume a lot of members here have cams that are either exact to the specs you post or extremely close that could chime in with how it drives, performs, and the dyno sheets but what is important is the results your guy tuning it gets, how the cars he tunes drive with it, what the dyno looks like when he is done with it, and any video or rides in cars he has done puttering around in a parking lot in 1st or 2nd gear to see how it behaves when HE is done with it. I might be beating a dead horse here but I think you get my point.
Good luck with your decision....