Yes, that's what a Spectre attack is
variants of Meltdown and Spectre exploit code that can be used to conduct side-channel timing attacks
All variants of Spectre are side-channel attacks. That's what Spectre is: a class of side-channel attacks using speculative execution.
And Meltdown is a subclass of Spectre.
While this new research is a solid contribution to the field, everyone already knew that coherence protocols were a target. They're mentioned in the original papers, along with a bunch of the other well-known timing side channels.