...in the early 70's, you saw mostly an extended housing and cable clamps:




By the mid to later 70's you were seeing a lot more exposed cable runs with stops,
or the other popular method of brazed on cable guides:



Stella was one of the companies that did the exposed cables early on, like on the one
above that I fished out of a bike junkyard in the early/mid 80's with no components.

It's not exactly a foolproof way of dating. There's not a good documentation of the company on the internet, to my knowledge.