Yes, there is 29 spot welds on each fender to cab. You can drill them with a special drill bit that will remove the welds but not any of the cab metal. It so happens I'm working on my race truck right now and can take a couple pics, except I have to figure how to load them into this answer.
I am starting this same repair. What drill bit do I need to drill out the spot welds and does any body have a part number for this inner fender? I've looked for about 3 days and can't find one in existence. Almost called it quits and got ride of the truck thinking I was going to have to do a whole swap. Any help is appreciated