I have a total of 5 fenders in the garage and two on the car - they are all spot welded. I have never seen one that is bolted.
I'll still have to dig out the bumper, it's behind some other stuff.
Here's a Valiant valance on craigslist:
64-65 Plymouth Valiant FRONT LOWER VALANCE PANEL - auto parts - by owner - vehicle automotive sale - craigslist
The only difference to the Barracuda is that the turn signals are integrated in the valance.