Dragonair may also be based on the imugi, a proto-dragon that resembles a snake and lives in water or caves, much like Dragonair. After an imugi lives a thousand years, a jewel (called a Yeouiju) will fall from the sky. If the imugi catches it, it will become a true dragon. The jewels on Dragonair's neck and tail might also be a reference to Chinese dragons's associations with pearls.
You can see the snake-like Dragonair has this jewel as part of it's design on it's neck. (And may I just say Dragonair and it's shiny are beautiful?) Dragonair is also part of the Water 1 Egg group, which further ties into it's possible Imugi origins.
Dragonite also looks like common depictions of Dragons, hence the "True Dragon" part.