Panzerfaust 3 was officially accepted and introduced on the 30th September 1992 and replaced both "leichte Panzerfaust 44mm" and "schwere Panzerfaust 84 mm Carl Gustav" during the next months. (no idea how long it took)
http://www.waffenhq.de/infanterie/panzerfaust3.html
Training for the later one had even ceased in '88, as far as I know from own experience. After all, serial production of the Panzerfaust3 already started in '89.
In game term this would mean starting the Pzfaust 3 in 9/92 and ending Pzfaust 44mm in 12/92 and maybe the Carl Gustav in 12/87. Btw., it was the M2 that the Bundeswehr was and is using.