What do you mean by legit? Airdrop is free, you do not need to pay for it so it should be legit as long as you join the 100% free airdrop. No matter how much is the value of the coins/tokens, as long as they do not ask you to pay some eth or ask you to provide private key then it is legit.
If your main point by legit is something related to the value then no one knows about it.
You pay with giving them your information...
They pay you a shitcoin, you give them your name, address, gmail account (google sheets), and dick size..
They then do with it whatever they want.