Interesting paint discoloration photos

So I was cruising the web looking for info and ideas on my rebuild and came upon this site where another guy in Italy was working to restore a VL1T.  It seems his project or at least his blog stalled out.  But in the mean time he posted some pictures I found very interesting.

Here is the address of the blog:

http://et3.it/topic/40029-restauro-struzzo-vl1t/

And here is one of the photos I found very curious:

This scooter is nearly identical to mine in age and condition.  Red primer inside the tank area, wheels and rims in the same shape.  And look at that discoloration!  Ivory to Grey.  Exactly the same as on my scoot.  I began to wonder is this simply an oxidation of old paint?

I looked very very closely at my scoot.  While some parts may have some oxidation effect othes are clearly repainted.  But the color similarities are very weird.  Anyway...