Looking for a bit of advice. Younger brother is looking at getting himself a first bike..2 models he's keen on, the Fatboy lo and the Softail slim. If he gets the Fatboy, he knows he can throw a Softail bobtail fender on but wondering if you can do the same with the slim or if anybody knows of another fender that will fit?

Cheers 

Pics below are his inspo for the fat boy.

Smokey is probably right as near anything is possible with time, money and skill but if you are asking if you can just change the slim guard over for the recent ducktail then you will need to change the struts that hold the guard in place at minimum, the 130 would look a bit odd in the 200 style guard though so another wheel and spacers would be needed to run a fatter tyre, then you may have clearance issues with the plastic shit at the front of the tyre, could check a parts schematic to see before hand though, the one below is handy.

You would also need to consider the taillight set up, the ducktail would look a bit odd without its light in place and the slim has all functions in the indicator housings, could easy sort the wiring to make it all work though.

His plan was a bobtail fender and a tribar style light. I didnt actually realise the rear tyre was only 130, i guess i just assumed they were a 160 like the standard on my Dyna. Ill have a beer and a chat with him anyhow, probably be me doing most of the work so the less fuckin around the better.