Oh Armature!!!!

I have been working on 201 motors, as you know.  Every armature that I have ever seen (it has not been many) look similar to this:  copper comutator and windings and then gray, metal armature

The armature from the motor I re-wired today looked like this:

There is brown, shiny, "varnish" on the armature.  I have no idea if that is supposed to look like that.  It looked so uniform to me I figured it must belong there.  So I left it.  But now I wonder.

It does not look like this armature that I pulled from that dreadful 201 motor  that someone really cobbled together on a re-wire:

That armature was stick and dirty.  I did try to clean it up and now it looks like this:

When sitting side by side, the armature in question does not look dirty.

So I just don't know.  I did put the motor all back together with the armature looking just like that.  I figure that I can always pull it and clean it if advised to do so.  I am off to post the question on WeFixIt now.  I am hoping someone there will help me out.