There are two areas of minor surgery that need to be performed. One is a brace towards the front that braces the frame side to side. It isn't on the 600s, but it can't be removed completely, as the plastic attaches to it. I cut mine off immediately on the inside of the allen head screws, and ground it smooth. The next part requires a bit more time, as the integrated tool kit holder (???) needs to be cut out from the rear of the plastic. It's an L-shaped area that needs to be cut out flush with the base of the plastic, then a cover needs to be fabbed up to stiffen the area up again. I used a piece of aluminum and riveted it in place.
After that, it should fit (did on mine anyway), but you'll want to check it over really good to see where it rubs. Mine started to wear through on my aluminum patch panel. I added some heavy duty weatherstripping anywhere it may rub. Now my tank fits tight with no slop, so rubbing will hopefully be a non-issue. Total time for the work after figuring out everything you're trying to figure out was a realistic 2-3 hrs, including running around getting things. Oh, you'll also need to drill a couple new holes and get a longer tarp strap.
Good luck!
