Am I allowed to close/lock a thread without archiving it?

I wanted to post a concept in an OOC section of the forum, but I wanted to lock it to replies.

My reasoning for that is: to encourage IC interactions rather than OOC hype, but to keep the concept information available for others to reference (just not respond to on the thread).

I'm a moderator so I can technically do that (lock/close a thread), but, should I? Is that weird? Does this even make sense?

Could you put it in a character's Pawprints topic so others can see but not respond to it, then link to it from your profile or signature? I'm just not sure about locking topics in active forums; can another CM weigh in on that?