Yes, except that if the last digit is not 0 then it only tells you "this is on the stable branch that started at the x.y.0 tag", and says nothing about year or

Yes, except that if the last digit is not 0 then it only tells you "this is on the stable branch that started at the x.y.0 tag", and says nothing about year or month. Stable branch releases usually happen about 4 months after the .0, but there's no regular cadence to them, nor any rule about whether there is none, one, or more from any particular mainline release. (The entire release process for them is largely separate from the main releases.)