Most body armor has the straps built in for variety of attachments which takes the place of a load bearing vest. But those are really only used in combat situations and when deployed for war. In more peacetime activity, to include base security, load bearing vests are still used.
Sorry, LBV's are not used in base security. DA Guards, DA Police, and Military Police are used for base security. All police gear. Granted LBV's are still used in training.