If they fold down, you should have a crevice between the outer two sections of the back of the seat (where the cloth changes from the seating area to the edge) There should be a loop to pull coming out a few inches from the top. It's possible they got tucked into the crevice, I suppose. Think of it as couch fishing.
Not all Intrepids are created equally. If your seats do fold down, there would be straps that you could pull on at the top outer corners or the seatbacks. If there are no straps there, you don't have seats that fold down. Most likely, your SE did not come with fold-down rear seats.
My 2002 SE has them. Then again, it had the $1200 option package with:
cargo net (mine was missing), illuminated entry, keyless entry system with two transmitters, bodyside molding, AM/FM stereo with single CD player and CD controller, 8-way power driver seat, cruise control and 16" aluminum wheels.
I'm guessing 60/40 split rear seat was included with that option in 2002. This list was for the 2004.
A few weeks ago a dumb ass mother F****** renter tried to fold down the rear seats in my 2000 model which twisted the frame on the seat. It was only when I got the car back that I noticed the rear belt was behind the rear seat. At first the renter denied this, but then his wife let it slip that he had tried to fetch some guttering in the car. The upshot is that I had to remove the bottom seat first and them remove the bolts that hold in the rear seat belt anchors and then lift up the rear seat over the three brackets and then bend the frame back into place. Pain in the ass job to do in the sweltering heat of sunny florida (home of moron tourist renters)