How is your system detecting whether a post/topic is archived as opposed to just locked?
I'm not sure what exactly you're talking about. What do you mean with "archived"? I don't track that or if a topic has been locked.
Some topics are locked by an administrator and cannot be unlocked by the OP after that.
I remember this discussion coming up on the Meta board, but I cannot find the original topic (not even with my own search engine LOL)