I wouldn't worry about having messed up the TPS, I've removed and cleaned my throttle body many times on my 05, opening and closing the flap with my hand and have never had a problem, and GM's service manual says itself to move the plate with your hand while cleaning.
As far as I'm aware, the throttle body and PCM should relearn automatically, but try this procedure I found on a w-body forum:
1. Reset ECM by pulling ECM fuse (underhood) for a few seconds.
2. With A/C turned off, start car and immediately put it in Drive with your foot on the brake.
3. If the car does not start initially, keep trying WITHOUT putting your foot on the accelerator.
4. Let the car idle in gear for at least 5 and no more than 7 minutes.
5. Shut off the car for 10 seconds.
6. Start engine, place in drive and let idle for 5 minutes.
7. Shut off engine.
8. Idle is learned.
Let me also mention that the 04-08 GP's, being that they have a drive-by-wire throttle body, have some delay or lag to them simply due to design. The signal from the accelerator pedal has to go to the PCM and then to the throttle body, which takes a split second. I've always had just a bit of delay to my throttle, and every drive-by-wire GP I've driven, so are you certain you just didn't notice it before because you weren't looking for it?
I personally wouldn't waste the money at the dealership either. The idle relearn (which I can't even find referenced in the service manual I have access to) is something you'd do if the vehicle was idling at an incorrect RPM range. It shouldn't have anything to do with throttle delay in my opinion. I flipped my upper motor mounts to rid myself of some of the perceivable delay, so maybe try that if you're interested. It just takes basic hand tools and some WD-40.