Take a picture of the interior of the truck. The 02-05 3rd gens have a different interior than the 06-08 ones. It sounds like you have the 06-08 leather seats if they’re all the same shade of grey. The 02-05 ones were a two tone grey/dark grey or black iirc.
If you have the correct seat for your year, then all the wiring should line up correctly for the airbags regardless of if they were originally not leather and then got switched. However, 06-07 had some weird wiring change mid year somewhere so they have two different shaped plugs under the drivers seats that may require you to either make a jumper between the two or simply change the connector from one to the other. I personally made a jumper when I added the factory heated seat option from 07 scrapped leather seats to my 06 cloth seats.
Do you currently have an SRS code being thrown on your dash...? Or maybe the little guy with the seat belt lighting up...?
Also, most if not all the 3rd gen trucks were included in the Takata airbag recall. If you have not gotten that issue resolved, then it would be worth a trip to the dealer to have them replace the airbags and possibly fix your state issue in the process.
If you give us a bit more info I’m sure we can figure it all out. I personally don’t like people driving around without working airbags. I’ve seen one too many nasty accidents that airbags didnt deploy in my line of work.