It is confirmed that a Cerberus Guard does appear and respawn in the same room you get the first Rig Upgrade in the display case. (Weapons and armor can be farmed instead of said boss of the same name).

I like this game a lot the rpg elements and the challenge of like say dark souls but to me armor in this game is little to nothing despite the fact I know rpgs and how to properly level up and upgrade the fact is if you can upgrade ur self early on you should see a difference in the damage u take. here I get killed very fast despite my best effort by dodging and watching enemy movement I wish u guys can patch this even if its not possible right now thank u guys