Thanks for the other info. I was told by the woman at the Freewheel bike shop that the Sekai 4000 and 5000 models were sold as framesets only. That explains the hodgepodge of parts on this bike, and the lack of continuity in others I have since come across. I also found the Yellow Jersey in Madison, WI has NOS decals for the Sekai bikes, but sold out for the 4000.
I've finished disassembly and have all the paint removed from the chromed stays, fork and crown etc. Now I've got to pick a color...for somebody yet to be found.