Ahoy, c.sam!
Yes, the sides are 'plated;' different from the other/adjacent silver areas. I grabbed a couple more photos and tried to capture that feature a little more clearly.
Hope those help.
I have it in my head that when the 2022 'Big Book' catalog first came out and the Lionel boys put up a YouTube video going through it page-by-page that they indicated the two A units of the Yellow Bonnet pair would be different from one another with respect to the way the yellow and blue manifested on the nose - that is, both would be prototypical but they would not be the same. The only difference I can see on these units is what shows up in the number boards, so I guess something changed between now and then (and I don't discount the possibility that my memory is faulty). In any case, I think Lionel did a nice job with these units.
Sam
ps: By the way, I am C. (Charles) Samuel