Yup. It's basically a route described as a list of hosts. One of the hosts is actually on the internet proper, and then the message would be transferred to each successive host along the way using whatever local links were available (including dialup modems) using a store and forward protocol.

As dedicated internet access became more common UUCP became obsolete.

decvax was DEC unix engineering groups vax on uucp/usenet. I believe it was the first system to move email in realtime. Microsoft must have been linked through this vax.