Hi,
It's partially true but for a specific reason.
When you view them under full spectrum lighting you can see the irridesence (sp? ) better and so they look great. I think it makes for killer photographs.
But it doesn't actually change the snake in any way - it doesn't develop better colours or healthier skin or anything as far as I am aware.
At least that is my take on it - I did have a full spectrum bulb on one of my old BP tanks and thought it made them look great for the 20 minutes a year they were out while it was on.
But side by side comparisons outside of the cage I never did see any marked differences.
dr del