I COULD BE WRONG.... from what I see in the pics, It is (was) the correct tub and is not 2 tubs put together...the seam is factory and that is where the extra length panel is placed in front of the rear wheels...BUT, I do not believe that the second set of doors would be cut like that from the factory. They would have three dimensional stamping like the front door areas for both strength and water run off from the top. I believe that they were simply cut out and the metal folded back. A small piece of pipe is welded on top for the door hinge and a fresh coat of paint hides all.... Now there where several companies that would take brand new Jeeps and "convert" them to special duty/opperations. Maybe a tour/safari Jeep. Also, almost all CJ-6's came without roll bars and the one in the pic doesn't seem to have the bolts showing through the side as a factory one would. And it's missing the side mounted spare. With it's age, almost anything could have happened. If you really want a 6 and like the doors on this one AND don't mind the price, then fine....If you want a stock Jeep to both drive alot, wheel in and really enjoy, I would go for the later 7's (like in the background).. I can say this because I have both and there is a world of differences...not all CJ's are the same.
1975 CJ-6 1983 CJ-8
1986 CJ-7 Laredo 1986 TJ-7 Trail Jeep
2003 Inca Gold TJ Rubicon