Difference in 06 and 07-09 hemi alternator

Just wondering if anyone out there knows the difference between the 2005 -2006 jeep 6.1 hemi alternator ( P# 421000-0360 ) and the 2007 - 2009 unit ( P# 421000-0660 ) Ready to get one for the conversion and looks like the older one is a little cheaper and can't see any other differences?

Any help much appreciated.