On my 39 I did go with the ribbed steel running boards from Northern classic trucks, I do not think those are available any more.
And my Wescotts front and rear fenders DO cut the mustard, unless I tell the car show audience that they are fiberglass with out really looking you can't tell.
Fiberglass worked for me, especially being painted black. Have fun trying to locate good front and rears especially for a truck that will not need major work.
If it was an original restorable vehicle and willing to overpay to make it a concourse, try and find steel V.S. market value and getting something running with a Flathead...yeah fiberglass