I have a 98 extended cab. Will a topper from a 95 extended cab fit.

 

Won't come close even a little bit.

 

Any details on why this won't work? The bubble on the back of the canopy doesn't seem to hang into the bed at all... so in theory a basic square canopy should work?

I am wondering the same thing... basically. I am looking at getting a non-fitted (just square, no curved forward edges to hug cab) canopy as well.