Ram got the already existing profiles (luckily), however Limited for Brutes is a weird interaction as you point out, as it can't be refilled. For Array, it's a new weapon with new profiles, so they could have skipped Limited there without problem. However I imagine they are mostly copy-pasted from grenade launcher with modified range to make then unique and 'new'.
It's kind of ridiculous how many grenade launchers are squeezed into this fairly small team now. I don't remember exactly but they probably all have slightly different names to make them incompatible with standard grenade launcher ammo, so they are mostly limited to a 'fluffy' subset of the normal ammo (choke/flash/frag/krak/scare/stun). The most 'normal' grenade launcher option to enforcer is pretty much a standard grenade launcher except it starts with frag & stun instead of rag & krak (it can however take krak among others as an upgrade). Then there is the assault ram sledge hammer which also is pretty much a standard grenade launcher (combined with the assault ram (melee weapon), it starts with choke & frag instead of frag & krak) (it can also take krak among others as upgrade). And finally now the grenade launcher array which unlike the others have slightly different profile, mostly the range is reduced to 18" from 24" standard (much like goliath stimmers twin-linked assault grenade launchers except no rapid fire here).
It could all be streamlined into standard grenade launcher, but that would be too boring I suppose?