Anyone have any idea what year and bike model seats will fit a 1990 Tourglide (FLTC). I am trying to find a seat that it more comfortable for my wife to travel on. THe seat that is on it is a LaPera, but I can't find a part number on it and it is making me crazy.

Pick up a catalog at any Harley dealer, for HD seats. Check with JP Cycle on the web. I would look for a Mustang seat. I had one , it was very comfortable for me and the Wife. She almost cried when we traded bikes. Or get on E-bay, you might pick one up there. Good luck tourglide.

http://www.mustangseats.com/Categories.aspx?intCategoryID=8&Category-Name=Seats />
http://www.corbin.com/harley/baggers/ />
Take Hollywoods advice and check those sites; also, check "Saddleman" seats 

I'm trying to find out if a 1990 FLT and a 1990 FLH seat are interchangeable

They will inter-change and ya might check out the mustang roll and tuck seat it's like sitting in your favorite arm chair. Rode mine all the way to Fl. and back and never gotcramped or saddle sore the whole time. And this is from a guy with a bad back!

love my harley sundowner..great seat at just under 300 bucks

Sundowner is the best seat I have found. Went 700 mills on one in one day on a road king. And I felt fine. My friend had a new Mustang seat on his glide and he was hurting.