A 519
The rules for Martial Arts styles in Oriental Adventures and Dragon Magazine #315 have never been reprinted anywhere else.
However, it sounds like you may be looking for the Monk Variant: Fighting Styles printed on pages 52-53 in Unearthed Arcana (and thus appear in the related section of the SRD). All of these fighting styles appeared in Dragon Magazine #310.
There were additional fighting styles printed in subsequent issues, using the same format, but none of these were included in Unearthed Arcana:
Dragon #334:
Kyokushinkai Karate
Wing Chun Kuen
Wushu
Dragon #337:
Metered Style
Dragon Magazine #346:
Sacred Path of Heironeous
Sacred Path of Hextor
Sacred Path of Moradin
Sacred Path of St. Cuthbert
Sacred Path of Wee Jas
Sacred Path of Yondalla