I have no idea as to when it was put together. Is there a serial number range you know of? Mine is MR165xxD.
Just recently and randomly looking around, from the few Marlin lever guns Ive seen on the shelves, it appears they are still having issues. Now whether or not those guns are earlier vs later, is anyones guess.
The exterior wood fit on mine was a lot better than some of the others Ive seen recently, but in my case, that was a misnomer, as the stock was inleted improperly, and needed to be shimmed to take up the slop, that wasnt initially apparent, until the gun was shot, and things loosened up.
The "AK" style front sights seem to be better, or at least, less common now, but the rear sights now seem to be an issue. The other two I looked at both had rear sights that appeared to be bent, and/or rolling off to the side. Mine were straight, although not zeroed, and the front blade was not centered in the dovetail.
The internal issues I had were something you wouldnt know until you fired the gun. I would assume they test fired them, and in my case, theres no way they could have missed it, as the lever jammed on the empty case on extraction, and you had to shake the empties out, and it wouldnt feed reliably from the magazine. Still, they called it good, boxed it up and shipped it.
I have two Marlins, the 336Y and the 1895G. Both are Remington era guns, and my luck has been 50/50. I was never really a big Marlin fan, and Winchesters were/are, more my thing. If they were still making the Trappers, I wouldnt have bought the 336Y.