Fred,
at first, you are right. LBA not BAL.
The Navy marked in this time only BAK or BAW (Kiel or Wilhelmshaven).
The frog looks without any doubt like a reissued WW1 frog, but a Luftwaffe-mark seems me impossible. There was no Airforce in Germany 1930 and the mark means BA, not LBA. BAM 9-30 must mean "Bekleidungsamt M�nchen, September (?) 1930".
I dont know, why it is brown. In the past I found more than one Reichswehr belts in brown leather. But may be, it was a private bought frog - look at the thin thread, the thin leather and it seems me a little bit to shiny for a chamber-piece. The markings could be put later on the frog, to sell it a little bit better.
Only for showing a LBA mark on a knot.
Regards
Kolibri