Doing a repaint, do I need to fully remove the fenders?
 

I'm peeping my 1981 911sc for a repaint, black to Tangerine. I was planning to remove the fenders, but considering just loosening them enough to remove the cowl seals and paint around the edges. Any have any advice?

That would work, Very similar as to how it would have originally been painted.

as long as your not finding any rust between the cowl and fenders what you want to do will work just fine .
if the fenders have never been off the car before you will find a spot weld were the two fender to cowl bolts are . take a stout putty knife and slide it between the fender and cowl and hit it hard with a hammer to pop the weld louse .

962 porsche, do you re-spot weld the fender when installing?

on some yes it all depends on the level of the job the customer is paying for .