Just got in a second Saidon and noticed a few differences between my first.
Can anyone that owns one confirm any of this?

Big difference I noticed between the first & second is the blue metallic paint.
Here are pics of the comparison of the backs showing what I mean.
First Saidon vs Second Saidon:


The Second Saidon I got also has more orange spray here and there.
First Saidon vs Second Saidon:



Third difference I noticed is the arm is sculpted a bit differently.
Thought I'd be able to replace the "burnt" arm on my first Saidon w/ the second.
First Saidon vs Second Saidon:

the metallic looks incorrect . it looks like its not original paint if the pic is accurate i see crackling as if the 2 chemicals in the different paints reacted . can you show a closer view of the crackle effect on the fins ?

Here's another one that's metallic blue.

not the color way but your paint on your fins looks incorrect because of the crackle .

if you need a better pic than this joe, let me know.

Interesting.

The arm on mine matches your non-burnt figure.

The paint on mine also appears a lot more green than blue - similar to Jim's.

the paint differences aren't too surprising, if you consider the several slight variations of the wolf-monkey/uchu-gejin?, also by yonezawa.

the arm sculpt variation is really interesting though.

In reading a Japanese blog about another Yonezawa toy, it was mentioned that the metallic paints used during that time were prone to oxidation. Different storage conditions might have caused the paint variation on your two.