[mothered]

I'm not aware of a time limit for edits (doubt there is one).

I'm not sure If It's still the case now (can't test It with staff privileges/permissions), but I remember quite a while back I was unable to edit my post after ex-amount of time.

I don't recall the exact time-frame, but It did happen on a number of occasions. In any case, as you've stated, simply edit the post. Given the member will/should Immediately notice the double-post, the time limit Is Immaterial.