The most important thing for me would be to get the vin and then ask Rivian to verify the warranty. Because chances are you will need to go back for warranty work at some point.
Vehicles in that time frame may or may not have the following depending on Rivian's mood the day they built your car.
12-volt outlet under dash,
12v outlet in front trunk,
wood trim pieces around the USB ports in the second row
updated stereo (unclear if the original was better or worse)
Extrusions on rear reverse lights.
Bracelet key (only available to launch edition vehicles, cannot be purchased separately)
The color of the bracelet key (It came in gray or yellow)
But none of those are terribly significant, and I would not avoid a car just because it was missing one of those.
It was also an update/improvement to the third row side airbags. But I'm pretty sure that came out in 2023 and you definitely won't have it.
Another dealer will know very little about the truck except "please buy it it's electric". As Sub said, get the VIN and check with Rivian on warranty.
Assuming it's under warranty, you'll just need to make sure everything seems in order. I have a '22 (not a Launch) and it's generally perfect, and all issues I do have are being taken care of by Rivian under warranty.
I bought a used 2022 Rivian R1T Launch Edition 2 years ago with 4000 miles on it. The salesperson was very honest right up front that she knew practically nothing about the vehicle including its systems. I on the other hand, had done a lot of research on it and ended up explaining a lot of things to her. Including how to adjust the vents.
Since I purchased the vehicle, I have had 2 remote service calls. One for a recall and one for a window that would go all the way up and then come back down 1/4. Both were done within a day of contacting Rivian. I have also had one Service Center visit that took 3 days and dealt with 2 recalls and the tonneau cover replacement. The Service Center completed the work early and Rivian provided a loaner vehicle (Non-Rivian) that I only drove home and back to the Service Center.
I will say this. This is our 3rd EV. First one was a BMW i3 which we bought certified and paid $16,000 for it. Second was a Mustang Mach E which we bought new. The Mach E was in service quite a bit for recalls and such but was a nice vehicle. The i3 was great until it wasn't. The EVU (environmental control unit) failed, and it took BMW 1 month to replace it. While replacing it they discovered that they had to replace the main computer and the Environmental Control computer. BMW's cost to repair the vehicle, which as I stated was under warranty, was $36,000. Again, we only paid $16,000 for the vehicle.
That told me all I needed to know about owning an EV out of warranty. For us, no thank you. Hard pass. But again, that's just us.
Early production, but as long as there is warranty left. Shouldn’t be a problem. Nothing in particular to look for beyond what you would with any used car: signs of collision repair, etc. Keep in mind ‘22 has two 12V batteries and warranty on them is only 3 years. They cost more than the usual 12V lead acid batteries. If replacement cost is a concern, look for ‘23 or ‘24 (single 12V) with more warranty left.
Nothing to really be concerned with. I picked up LE with 32k last September. After purchase I was able to get a full service history from Rivian which gave me additional piece of mind. The main thing I'd want to know is if it had the 12V's replaced. Mine went out right at 35,800 miles. The mobile tech who came out to replace them told me not to drive over 200 miles before he closed the ticket out end of day.