That is correct, there are only three recognised colors of labs - yellow, black and chocolate. (Which always seems like a strange naming scheme to me ... shouldn't it be either yellow, black and brown ... or vanilla, licorice and chocolate? LOL)
Anyway ... white labs are just very pale yellows bred to very pale yellows, etc. Silver labs are a variation of chocolate. Both white and silver is a fault in labs, and these dogs could not be shown, and should not be bred, according to AKC standards.
Paying $1,000 for a lab of any color is simply insane, when labs and lab mixes are probably THE most common dog put to sleep in shelters. I know they are around here, anyway, hands down. But paying $1,000 for a dog that cannot ever be shown in conformation due to a color fault is REALLY insane. What are people thinking!?
A white animal is not the same thing as an albino. An albino would have pink eyes, clear toenails, no color on them at all. The gene for albinism is often genetically linked to the gene for deafness.