No, I believe you should be completely locked out of any title or mount you could have obtained a patch later. And don't get me wrong, I don't even raid anymore because of the same reasons, but that doesn't make me feel entitled to get all that fluff.
I'm absolutely against making the game even less different and less about skill (or time investment even, it remains an MMORPG for crying out loud). Because linking achievements with a timestamp on it is going to make you feel superior.. Seriously?
Either you do it now, or you miss out.