So I got LLD a couple weeks ago (I was very careful to steer away from midfakes) but I'm having so e doubts. Is the code J0512 a midfake? It seems to be in the timeline but idk

Hard to say. I wouldn't expect it to still be manufactured in 2012, but checking the subreddit, they only list midfakes with codes starting in 2013 onwards, so it looks promising.