No, I wouldn't think so. I'm not all that familiar with Japanese frames but I can't say that I've ever seen a Japanese frame built with Columbus tubing. I do know that Japanese frames are held in high regard due to their build quality. If the previous owner is correct about the frame being built from Columbus SL and the dropouts are Shimano, it could be a frame built by a small builder and perhaps local although having such an extensive serial number really suggests that this outcome may be incorrect. Also, the stamping of the serial number is machine done - doing that by hand is really difficult - suggesting a big frame builder.