Thanks for the file, Mark.
The creator of this model has certainly not taken care of normals. The problem here seems mostly to come from an sloppy way of mirroring elements. The second most part is given with merged objects, whereby a group of connected polygons is reverse to the other group of polygons.
The tools in C4D are Align, as I said, first polygon rules, or reverse. They are not suitable here for select all and click. Since the first one is often already off, or even worse, they are not connected groups in single objects. Sorry.
I did the first group, with 568 objects; It took me nearly half an hour to do that.
First I selected all objects from one main group, and selected all polygons, so I did not have to do it each time to see the normals.
Then I used to use the Viewport Solo Selection for the main work, as well as the short-cut S (while the mouse is in the viewport!). Clicking on an object, one can go down with the arrow keys in the Object Manager. The short-cuts for Align is U~A and for reverse it is U~R.
After a while I went to Windows> Customize> Customize Commands, and created a new palette with the functions I needed, S, U~A and U~R, to be faster. I stay in the rectangular selection to sort more problematic objects.
Not the most fun work, I know. So, if you can get hold of the creator, perhaps s/he has a version before mirroring parts, or a better version…
Here is a little clip, showing my workflow suggestion:
https://www.amazon.com/clouddrive/share/yAl5XJd9GkK0PfqME2AvZ8ne3Dm6FFvqs70sEhtV4PI
I googled if I could find something, but no luck, but honestly, I did not expected it. The only measurement combined polygon groups in a single object can have is the first polygon each time (same orientation) or that the origin (axis) could be used as evaluation (i.e., axis is inside.), but no luck. Since many objects are not “volumes” a clear inside and outside wasn’t even easy to evaluate for me while doing it manually.
All the best