1.2

Is 1.2 still the curerent version of M2TW without kingdoms?

No, it is 1.3.

But AFAIK, 1.3 adds absolutely nothing to the single player game. I believe it just provides compatibility - allowing you to play with those who have kingdoms. It is probably essential for MP, for PBMs and maybe some mods.

So is there any point in getting 1.3 if I don't play MP?

No
1.3 Fixes some instances of floating settlements in Medieval II. There is really no need to upgrade to 1.3

If it fixes floating settlements, then I wonder why the lake in the swiss alps map with a huge city seems to be overflowing :laugh4:

Anyway, absolutely no point in getting 1.3 unless you play with others who all have it.
Some say that installing 1.3 might even give you SecuROM