Yes. Gareth will form the more comic-traditional Hunters after the fall of Terminus, along with the few other Termites who survive the onslaught as well.

 

Just noticed this in the official episode synopsis on the AMC website--

"Months after Rick's escape from Terminus, a masked stranger marches down the railroad tracks. He stops to see the Terminus sign Rick modified, and hangs his head. He removes his mask. It's Morgan."

Guess that clears that up. So it's definitely after the Hunters and the Hospital when Morgan finds that sign. You think he'll be able to follow the trails Gareth made to hunt the group, which are also months old, to catch up with them? It seems like after several months the group would be well on their way; because my original theory is this Morgan scene is from the end up the season as it's winter time when the group arrive at ASZ. But; if they're in Alexandria and he's still in Georgia, it seems a pretty daunting task for them to find one another. Unless somehow he's actually able to follow the signs, and the tracks, maybe he can catch up to them, especially once they reach ASZ and stop moving. Morgan definitely appears to be in a state of great clarity; having won the battle for his sanity; the inner-conflict he was suffering through last we saw him. With that being said; what if Morgan is actually on a "Find Rick Mission"; and when he "woke up" from his crazed stupor; he realized he needed to be a part of something, and that Rick and his people were that something. I believe he even may have managed to locate the nearby prison and heeaded there first, remembering Rick talking about it; but when he arrive he fins an overrun graveyard. So he set out again; and using tracking skills, common sense and deductive reasoning and deduced that the survivors of the prison tragedy followed the tracks until they found the Terminus signs and then followed those. But once he happens upon the altered sign he knows there is something unsafe about Terminus and heeds the warning. I seriously believe he's looking for Rick.