My '87 E26 looks just like the one in the color brochure on this website. Has the extra interior teak around the ports and the rear bulkhead, etc., as well as the wide gunnel stripe. I have a Universal engine, not the Westerbeke described in the literature, however...I don't know if this is significant. When I get a chance, I will check the hull number. The literature specs describe the ballast as "cast lead internally mounted". My boat shows no evidence of an external seam as on the boat that Surabaya shows. I am assuming that I have one of the last boats with internal ballast.
I suspect that the change to externally bolted on keels was to allow for the winged keel option that started in 1988 or 89.
I had, some years ago, a 1989 E28 with an external wing that was built in Mexico. I don't know if the 28's ever had internal ballast, but the later boats with wings certainly had to be external!
I had alot of grief with the glass work on that boat! The two tone deck developed all kinds of huge cracks, there were serious voids, bad hull blisters below the waterline, and vast areas of the hull behind the liner that never fully cured! I wonder if I am alone in this...I always thought that this affliction was limited to, and commonplace in boats built in the Mexican plant.