72 K20 build thread, need good name

[Rust Buster]

Teardown continues...
Got the front clip, master cylinder, heater core off. I'm getting ready to take the cab off this Friday (working the engineering solution for that).

Finally found out what the smell was that came when I turned the heater on...Quite a big nest for the little feller. He's in the lower right in the 2nd pic, you can see his tail. So two questions...

1. Should I replace the evaporator core while I am in there to be safe?

2. Are these leaf springs stock? At first I thought they were sagging a bit but doing research, all the stock replacements for 72 K20s are 3 leaf while I have 4. Any thoughts? I can't imagine why they wouldn't be stock...