Não, os bônus do mesmo tipo não se acumulam
Essa regra ainda é válida para o Starfinder, e você pode até mesmo convencer seu GM a usar duas armaduras diferentes, apenas uma delas fornecerá bônus enquanto estiver gasto (provavelmente o mais alto).
When multiple bonuses apply to the same value, different types of bonuses all apply, but in most cases bonuses of the same type do not add together (or “stack” with each other), unless a source specifies otherwise. (For an exception, see Circumstance Bonus below.) Bonuses that do not list a bonus type do stack, both with each other and with all typed bonuses. Such bonuses, often referred to as “untyped” bonuses, are among the most utilitarian of all bonuses in the game.
E novamente:
Armor bonuses don’t stack with other armor bonuses, but they do stack with all other bonuses to Armor Class (such as a Dexterity bonus). Armor bonuses sometimes specify that they apply only to your Energy Armor Class (EAC) or your Kinetic Armor Class (KAC). Most suits of armor provide armor bonuses to both EAC and KAC, though the specific armor bonuses a suit provides to each value often differ, as noted in the armor’s description. An armor bonus that doesn’t specify which Armor Class it applies to applies to both.