Just to add to this. Was his old armor - pure beskar? or just partial? They kept showing him have to repair it, like it was busted up. Maybe had some beskar parts, but mostly wasn't. If it was pure beskar, that Mudhorn wouldn't have dented it.
So, as he was becoming "beskar rich", he was literally wearing his money and just went with the all 'silver' look. I always took it as him showing off to the others in the clan. Mr. Fancy Pants.
Now, you see it in his upgraded ship, which is all silver. But he keeps the brown clothing, which also went with his original busted up armor.