12 ft? 600 pounds? That's a Tuesday story down here. Big, no doubt but unless they found that dude with 2 sink holes, a German U boat, JonBenét Ramsey and Jimmy Hoffa in his stomach, it's Florida being Florida.
If that thing is 12', it weighs more than 600lbs. I got one that was 10'11 that was 850lbs and my buddy got one that was 10'1" and it weighed 1024lbs. Length and weight are very relative and that gator is not malnourished looking. So one has to be incorrect, weight or length or both. But it is a big looking gator.