I finished replacing the plastic cam gear in my 445. I recorded some youtube video of the replacement. Also below is a spreadsheet of the parts, and some identifying info that came from folks on this list. Hopefully this will make it easier for anyone else that has the plastic gear fail.
FD620D Model Reference (sticker below front accessory shaft, although many are missing)
Engines marked FD620D-AS01, BS01 have a plastic cam gear
Engines marked FD620D-CS01, DS01 have a steel cam gear
JD 445 Model Year Serial Numbers for Reference 1998 started steel gear
Steel cams starting with...
FD620D-CS00 - Beginning serial 153727 - Model F911
FD620D-DS02 - Beginning serial 149283 - Model 425
FD620D-CS01 - Beginning serial 150198 - Model 445
FD620D-ES11 - Beginning serial 152490 - Model 6x4 Gator
Thanks for all the help from this forum! It was not a bad job at all especially knowing I had support here if I needed it.