Originally Posted by T-Mar

Theft is the major reason to keep a record of the serial number, so the fact that the bicycle was stolen would not necessarily mean that you don't have the serial number.

Regardless, the bicycle was equipped with Shimano 600EX, which places it 1978-1983. The Tange tubing decal, as opposed to Champion signifies a hi-tensile tubeset. Manufacturers rarely applied tubing decals for plain gauge hi-tensile, so it was almost certainly one of the butted sets, either 101 or 102. Both would be consistent with the era and components. The decals were available in this style during this period and it simply looks like a faded version.

Most Japanese manufacturers of the era offered lower mid-range models with this combination of tubeset and components. Manufacturers and bicycle trading companies in the Osaka region included Asia Machinery, Chitose, First Cycle, Fuji, Kakiuchi, Kashima, Kuwahara, Kyowa Sangy, Maruishi, Matsu****a, Mitsui, Mori, Nichibei Fuji, Nikko, Shinwa, Yamato Gumi, Yokoyama and Zushi. Undoubtedly, there were even more.