I haven't tackled my 70 that I received in a million pieces, but I know on my 50 and 53 that it is easier (for me anyway) to install the outer on the inner and then put on the truck. Make sure you have a couple helpers though to avoid dings. Make sure everything is VERY loose. Have a tapered pin to help you line things up by inserting into various bolt holes. It's also a big help to remove the front wheels to give you lots of workspace if installing the fenders as a pair or group.
Last edited by Fox; 04/26/2017 4:56 AM.