Nuts are only used when the housing doesn't have threaded bosses. Threaded bosses in the housings are common on small electric motors and they don't vibrate loose in use. Not sure why you think the alternator would either, that type of assembly is extremely common.

Skip the loctite, it'll make disassembly in the future nearly impossible. If it makes you feel better at night, you can add locknuts, but it isn't necessary.

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]