They're not permanently sealed. But to keep your supercharger properly within the Toyota/TRD drivetrain warranty you can't break the seal to even check the supercharger oil level until after it's out of warranty at 60K miles. By that time it's about 30K overdue for the oil being at least checked.

There's a thorough post about it here:
http://www.4x4wire.com/forums/showflat.php?Cat=&Board=UBB13&Number=315143

And anthraciterunner had a clarification that the proper tool to use is a T-27 Torx bit in this post:
http://www.4x4wire.com/forums/showflat.php?Cat=&Board=UBB13&Number=357281
Um, do the T-27 and T-30 both fit due to their taper?

Jeff
2000 4Runner SR5, supercharger, rear e-locker, ARB front locker, 285/75R16 MT/R's, custom bumpers & skids
2007 Tacoma double cab 4x4 - stock