It's really pretty simple.
If all the points are the same piece of wood, and still connected to each other, then it's what is called a full splice.
Veneers don't matter.
Most all "house cues" are full splice.
If you take a full splice and cut it so the points are no longer connected, then it's no longer a full splice.
There are a few fancy cues who appear to be full splice, but in reality they are not. They are seamed together in different places than normal, but they are still seamed together, so they are not a full splice.
Full splice is just a construction method. It's actually pretty easy, but not so if you are particular about the points being even.
Full splice's were created for a couple of reasons. First, to add surface area to the glue joint. The glues were pretty bad back then, and they needed lots of surface area to make sure they stayed glued together. Second, it was a way to attach a heavy wood to a lighter one. Back then all the cloth was slow, so cues were routinely at least 20 to 21 ounces. With today's cloth we just don't need the heavy cue.
Just my observations from 20+ years with cues.