88/5 speed is a little easier because there is no grinding on the neck. '05 and older you just need to grind off the back of the trees. "05 and older have narrower rear fenders and will accept all sorts of older FLH fenders.
This is my father's 2005 Super Glide meant to clone late 70s or early 80s FLH.
and my 2008 meant to specifically clone a 1959 FLH. I had to make custom rear fender out of 2 new Road King fenders and lace up a modern Road King rim to the Dyna hub. Much easier with a 2005 and older if you are trying to go for a certain year retro-mod. If you are just wandering in the FL-Dyna wilderness, by all means do as you like, experiment and show us what you did so we can all learn new tricks. Have fun!