Beta 1.2_02 was released mainly to change where skins are downloaded from.
Changes
Skins are now downloaded from Amazon S3 instead of minecraft.net
Lapis lazuli ore now drops 4 - 8 Lapis Lazuli per block mined (increased from 1) on single player only (Minecraft Beta servers have not been affected yet).
Beta 1.2_02 is the oldest version in the launcher to have working skins.
However, if the player changed their skin after 1.8, the last skin the player used prior to 1.8 will be displayed. This occurs in all versions after Beta 1.2_02 until 1.3.1, and it is currently unknown why this happens and why 1.3.1 is the oldest version to display post-1.8 skins.