Well, in BG1 you could have the game pause after everyone has taken their combat 'round'. So it more or less was actual 'turn based'. Not sure on the others offhand.
No, no, no! This was a marketing move to appease AD&D fans. Adding an automatic pause every sixth second in combat (which is what this was) doesn't change squat. It's still real time with pause. Turn based, by its very definition, requires that each character in combat does his actions before the next character in line can do his, and so on, until everyone has moved and it starts over from the top of the list. There is middle ground, but it's not at all similar to the BG approach. An example would be a system where each side in the battle can move their characters in any order they like, moving all of them (perhaps even going back and forth between them. Think XCOM) before the other side can do anything. This is still true turn based gaming. Once you add time as a major factor (with the sole exception of time limits for how long you can spend doing a turn) where every character acts at the same time, the system becomes real time.
There's also something called simultaneous turn based, but that's its entirely own thing, completely separate from regular turn based (and still not at all similar to real time). It's also almost never used, because 9 times out of 10 it sucks.