It may also be a good idea to check the pedal bushing. They get worn and let the pedal flop around a bit.
I might add that this is nothing unusual on the trucks I've experience...a 50 and a 52.
If the cab mounts are tight and not worn you may do like some others have done.....file off the side of the toe board where it rubs to get rid of the squeak?


1937 Chevy Pickup
In the Gallery
1952 Chevy Panel
In the Gallery
More photos
1950 Chevy Coupe
Pictures!

I'd rather walk and carry a Chevy hub cap than ride in a Ferd.
I can explain it to you, but I can't understand it for you smile