1957- Chicago Musical Instrument (CMI) purchases Epiphone (announced May 10, 1957). It had previously acquired Gibson in the spring of 1944.
December 19, 1969- ECL Industries Inc. ( "Ecuadorian Company Limited"-incorporated in Delaware and a U.S. subsidiary of a Panamanian corporation of the same name)officially takes over CMI. Norlin is an amalgamation of the first syllable of ECL's chairman's first name, Norton Stevens and the last syllable of CMI's president M.H. Berlin's last name.
1970- ECL's U.S. operation becomes "Norlin Industries Inc." and the Panamanian corporation becomes "Norlin Corporation". CMI remains a subsidiary of the U.S. operation.
End of US built Epiphones, enter the short life of pre-FT Japan built Epis.
1971- Beginning in the spring of 1971, Norlin imports Matsumoku/Aria-made models from Japan which have been re-branded as Epiphones. These models use the familiar blue "Kalamazoo"-type Epiphone interior labels and early models make use of actual left-over Kalamazoo labels bearing the "Union Made" designation.
Continued use of the Blue 'Kalamazoo' label. Very early models had the "Union Made" lined out and "Made in Japan" rubber stamped in lower right. Over the years the black in has faded on these edits. -- buyer beware
Enter the Norlin, Japan built FT models:
1972- A merger of Norlin Industries Inc. and CMI operations creates "Norlin Music Inc." A few years later the name was again changed back to "Norlin Industries Inc.
1975- Matsumoku begins production of a Japan-exclusive line of higher-end Epiphones. These at first are sold only in Japan but by 1979 the arch top line is distributed world-wide.
Enter tan colored "Lincolnwood labels.
Epiphone corporate operations are moved to Lincolnwood, Illinois. At about this point Epiphone began using the "Norlin" square label replacing the blue K-Zoo-type label. The higher-end line of Matsumoku-made Epiphone labels continue to reference "Epiphone/Kalamazoo"
June 1979- Norlin merges Gibson Inc. into Norlin Industries Inc. and Gibson ceases to exist as a manufacturing operation becoming only a brand name as Epiphone had previously become.
Exit "FT" models. Replaced by "PR" models
July 1983- he decision to close the Kalamazoo factory is made and a year later in September,1984 operations ceased in Kalamazoo. For the last year of operation the Kalamazoo factory diversified into making things like clock cases, water bed frames and conversion van parts to keep the employees working.
1983- Most Epiphone guitar production is moved to Korea and contracted out to Samick. Matsumoku continues to make the higher-end line of Epiphone instruments in Japan. Some Epiphone instruments at this point in time are also made in Taiwan and Indonesia
January 15,1986- "Gibson Guitar Corp." is created when Henry Juszkiwwicz, David Berryman and Gary Zebrowski purchases Norlin's fretted instrument division. GGC later becomes Gibson Musical Instruments (GMI).
1985/1986- While Henry J and company were negotiating for the Gibson name, three former Gibson employees, Jim Deurloo, Marvin Lamb and J.P. Moats were working their own deal to take over the former Gibson factory at 225 Parsons Street in K-Zoo and begin making "Heritage" guitars.
June, 1989- Gibson opens up their Bozeman, Montana acoustic operation Gibson having previously used the Nashville factory whose climate was determined to be unsuited for acoustic production.
Hopes that clears some things up regarding dates and such. For more fascinating information check out " Gibson Guitars: 100 Of An American Icon" by Walter Carter.
If I were one to wager, my bet would be that the PR-720S, the subject of the original post, was made by Samick and dates to September of 1991.
Have to go mend my nets and tend my lines.