From what I've read from Finnish military sources, BUK Telar units would not seem to have device(s) needed to detect if target is a friend or foe. (at least the models that Finland uses) They say the FF detection is done by separate radar (or control) unit.
It looks like it does
A Buk TELAR vehicle is fitted with radar, digital computer, missile erector and launcher, friend or foe identification system. It is operated by a crew of four and carries four missiles.
Cheers
Martin