Yes that's true. Also interesting is, AFAIK, DynamoDB does not follow the Dynamo paper. DynamoDB uses an architecture based on single-leader replication, and the Dynamo paper describes a process where a coordinator node is in charge of replicating to each node. If I am not confused, any node among the top N nodes in the preference list can act as the coordinator.
(This information may be slightly out of date at this point)
(This information may be slightly out of date at this point)