Definitely! And it would be pretty interesting if that also happened with Adventurer's Guilds
If I understand how guilds work correctly, they form when a number of dwarves and/or residents all have the same industry profession, so farmers get one and craftdwarves get one etc.
Assuming* that you build a fort that attracts the right kind of guests and those guests become citizens then
hypothetically you would get a "adventurer" guild based around the
visitor profession of "warriors", which consists of mercenaries and monster hunters.
Admittedly it wouldn't be a adventurers guild in the traditional sense of them gathering in parties at the guild and venturing off but its close-ish.
Actually thinking about it, RPG adventurer guilds are somewhat mercenary in nature, they accept "quests" for reward/payment so adventurer guilds are actually a specific offshoot of mercenary companies where each squad or "party" operates independently, the company focuses on bandits, night creatures, semi-mega beasts and mega beasts while avoiding wars and military actions, so maybe they are kind of but not really included already?
If not it does seem like a relatively easy addition, possibly even easy enough to slip in during post release bug fixes, but I wouldn't bet on it given the new focus the Dev's have on the Steam release, it would have to be really easy to be considered for addition now.
Note *: to Assume is to make an ASS of U and ME, this is not a guarantee.