That post you refer to where 'package' was used for a female crotch was the only time I've ever seen that.
'Junk' and 'package' are both male only terms in my experience - tho' 'junk' is relatively new to me, I must say. Certainly I have understood and used 'package' as male genitalia for as long as I can recall - 'junk' is something I would say has only come in to my repetoire in the last 4 to 5 years.
Also - I, personally, would use 'junk' in reference to clothed or unclothed male genitalia - 'package' I would only ever use for clothed 'junk', IYKWIM.
I guess it is the 'wrapped' reference of 'package' that makes me think that way.