Not really there are the Kofiau and Waigeo island types but not really sure if they will definately stay the highlighter yellow they are known for definately. Some say they will others say they don't and I don't have enough money to see for myself lol. There are morphs though, high yellows and mustards. I know theurbanchondro.com had some stunning snakes.
I think what you are talking about though is ontogenic colour change and in the wild is reported to take place roughly when the snake is between 53-59cm in length and around one year old (according to one study and it only includes the yellow phases snakes, not the red) and the process is very rapid. However in captivity this isn't the case and can change anywhere between 6 months and onward into a number of years. Either way, it's something that happens and isn't something that is permanent.