No.

Atbash works by folding the alphabet back onto itself.  A becomes Z, Z becomes A etc.  it’s a very simple substitution that is so completely unlikely to have foiled anyone  for 15 minutes much less 20 years that it was with some amount of humor that I approached a deciphering attempt by this method.

OBKR
UOXOGHULBSOLIFBBWFLRVQQPRNGKSSO
TWTQSJQSSEKZZWATJKLUDIAWINFBNYP
VTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR

becomes

LYPI
FLCLTSFOYHLORUYYDUOIEJJKIMTPHHL
GDGJHQJHHVPAADZGQPOFWRZDRMUYMBK
EGGNAUKPDTWPACGQXWRTPFSFZFVPXZI

Oh that’s a shame, it didn’t work.

-Kryptosfan