Difference in 1940 and 1947 ford truck rear fenders

I believe 38-41 will interchange, and 42-47 will interchange. I know the 38-41 will have a fuel filler hole.If I'm not mistaken the bed on the 42-47 is 3 in. wider. So are the 42-47 narrower? If so how much? How much different are the areas where the running boards bolt on? Reason I'm asking is I need a set for the back of my truck and wasn't sure if the later fenders would work on my 40 bed with 40 boards.

 

So do you happen to know if they are the same width? Thx

 

Ok, thx