Gen 1 frames

Are the frames from a 1st gen Tacoma and a 2nd gen compatible? I’m looking for a frame for a 2003tacoma and mostly find from 2006 forward

 

Not compatible

 

I’m looking for both complete rails that are rusted out from the cab to the rear bumper
Are they available?
I have only found repair kits

 

You’ll need to find a donor truck and do a frame swap, and rustproof the donor frame. Toyota stopped making these frames some time ago. Your best best is a southwestern truck that hasn’t seen much road salt.

If there’s enough metal to weld to, you can weld on reinforcements, but they’ll probably only delay the inevitable.