Both gangs are the same.They don't appear in the game outside of using cheats or mods.As said, they appearance is identical to the Varrios Los Aztecas ones,with no changes in the look.They behaviour is different - they won't attack Carl at first sight, even, they don't want to confront him.
Ways to spawn
The gang can be spawned in various ways, cheating being in all of them:
1.Put on the cheat BIFBUZZ (PC).Now all gangs should appear on the streets, underneath Varrio's driving Sentinel's.These are members of either Unused Gang 9 or Unused Gang 10.
2.Various save game editors can be used to add a territory for the gangs, and have them in a district.
The gangs can be customized, by changing they models to other ones and changing which cars they drive.A full tutorial about this can be seen here: http://www.gtaforums.com/index.php?showtopic=466531 .