I had my first ball for almost 10 years now.
She was a wild caught "male" that I bought for $20 from a guy that bred snakes down the road from me.
At that time, she was actualy very darck in color, more on a chocolate than gold. With a very dark head.
Now, She is all gold and greenish and a very light gold head.
Im not sure why they change, but its pretty cool. But nothing to be concerned about.