The Buk M1-2 TELARs in Russia are in fact equiped with two types of missiles
All we know from wikipedia is that it was designed to accommodate those older 9M38 missiles, not that it still uses them. They were first deployed almost 30 years ago, in 1976.
New missiles (9M317) for Russian BUK M1-2 were a significant improvement in all areas and that BUK has been deployed since 1998 - 16 years already. It's not a fact that Russia still uses older, less powerful missiles.
Anyway, these questions should be directed to the author of the hacked letter - he was the one who identified the fragment and mentioned Buk M1. He must have reasons not to include Buk M1-2 as another possibility.