First, here’s a link to images of other Model 12’s.
https://cailleoutboards.com/model-12/index.html
I’m attaching an image of mine after it was reclaimed.

It looks to me like the cylinders are gray or possibly silver. You can p[aint the crankcase the same colour as the cylinders. Transom bracket is silver. everything from there on down is bare metal/ Some parts might be nickel plated. the lower unit is just bare aluminum. Tank flywheel and rope sheave are polished. Hope this helps
Best
PM T2
He's livin' in his own private Idaho..... I hope to go out quietly in my sleep, like my grand-dad did..... and not screaming, like the passengers in his car...