I've replaced the oil seals on both of my bonnies, without removing either the supercharger or the snout, but I'd only recommend it if the supercharger has low miles and has no other known problems. In my experience, the nose oil seals are prone to leaks.
Once the pulley and the seal retainer were removed, I made a small puller out of a large washer and 3 small screws, and carefully drilled 3 holes in the seal and slowly pulled it out, wiped the mating surfaces, and carefully installed a new seal. I used the Vition verison of the seal rather than the Nitrile rubber version.
'99 Bonneville SLE, white, 112,000 miles
'02 Park Avenue Ultra, white diamond pearl, 88,000 miles