I saw this message on Coinbase
Update: We anticipate enabling Bitcoin Cash (BCH) buys and sells in early January 2018. Sends and receives are online. If you held bitcoin on Coinbase on August 1, 2017, you should now see BCH in your Account.
Does that mean "since" August 1? 'cause I have had Bitcoin since October on Coinbase but I don't see any BCH on my account. However, I sent all my BTC to GDAX (Coinbase & GDAX should be the same).. But does that make the difference?