Identifying J-50

[Feast of Steven]

I recently acquired an old Gibson J-50 that at some point was re-sprayed (tobacco sunburst), and apparently had the head stock scabbed in as there is no serial number on it and a clear line where that must have been done. It's likely that they even painted the Gibson logo back on it. All-in-all, it's an awesome guitar and I got it at a great deal given the fact that it's been refurbished and has no clear way of being identified. I'm a player and not a collector, and it plays and sounds like a J-50 so that's good for me - the tobacco burst is a nice touch, and whoever did the restoration seems to have known their stuff, looks and plays nicely. However, I would like to try and identify/authenticate it if possible, and maybe establish some kind of history on it. The only info I have to go on is the seller claims it's a '68, and there is an aftermarket serial sticker in the soundhole that claims the serial is 2168N - I haven't seen that in any of the naming conventions for Gibsons serials/FON, so I'm curious as to why they would write that. See pics for details. Any info or advice on it would be greatly appreciated, thanks!