Are you referring to the fiberglass header panel – which attaches to the front edge of the fenders and contains the grill and headlights, as the nose?
NOS Header Panel 1977-1979 Chrysler LeBaron Fascia Headlight Panel NEW 5263121 | eBay
If so, “I think” all M-body header panels will interchange – but there might be a difference on the hood on one version (so hood will need to be changed, as well) – again, “I think” (no first hand knowledge on trying to switch out with a different version header).
I have removed and helped remove/installed the header on about 50 (or so) M-body’s before. It helps greatly to have a helper – especially on a header you are trying to save. Also, the metal studs that go through the fender are the tough part. The studs tend to spin in the fiberglass – which damages the fiberglass as well as stay attached to the nut making it very difficult to remove.
I recommend soaking each of the through-fender stud nuts with rust penetrating oil a few times before attempting to remove those nuts. At one time I also modified a pair of smaller needle-hose vice-grips – making the thickness of the jaw thinner (via bench grinding) – so I could reach up behind the heater to grab ahold of the studs if they were starting to spin. The modified tool would only work on the lower studs, so it helped but not for all the studs.
On the assembly line, M-bodies were painted with the header panel and the trunk extensions detached (separately) and attached to car later.
Here are some of the differences in the M-body headers (but not a comprehensive list):
1978 Lebaron
1980 Lebaron
1983 Fifth Ave
1986 Diplomat