player.is_spartan
This function checks whether a player should spawn as a Spartan based on their team settings and (when relevant) their preferred species. Its result is not affected by a script forcing a player into a biped of a different species.
Example
for each player do if current_player.is_spartan() then current_player.set_loadout_palette(spartan_tier_1) alt current_player.set_loadout_palette(elite_tier_1) end end