Bronze color in one single chamber on a revolver cylinder

[Alp Arslan]

Now this may not be of much importance pertaining as to fit or function but curious to see if anyone else has seen this occurrence in their revolvers.

I had taken delivery of a spare cylinder for my LeMat .44/.63 truck/backpack gun and was wiping down all the heavy cosmoline from the cylinder before I fit the cylinder to the revolver by slightly widening the locking pin apertures in the back of the cylinder.

Once the cosmoline was cleaned off completely, I found that the bottom of one of the chambers had a deep bronze color. The rest of the chambers are bright silver but this one appears to be deep, rich bronze gold. I found this quite amusing.

Have you guys ever seen this before?