I tried the manuals through helm and it was problematic for me.  I tried
calling but their office hours would delay me.

I went through motorcraft, no issues at all:
http://www.motorcraftservice.com/vdirs/retail/default.asp?pageid=&gutsid=

A better question might be what you are trying to accomplish. There is no
such thing as the 'entire ac unit'. The A/C system consists of numerous
components, located in different places. Some of them are easier to replace
than others. If this vehicle still uses R12 (Freon) and you are thinking of
converting to R134a, there may or may not be a need replace a couple parts,
but certainly not the 'entire unit'.