I'd contacted those running the auction and here are the facts of WHICH of The Edge's Explorers is being auctioned:
Dear Jeffrey,
We appreciate the dedication and interest in the U2 community regarding the Edge’s items in the upcoming Music Rising Icons of Music II auction.
As fans of U2 know the Edge has a large collection of instruments, including back up instruments. This particular Explorer is his #3 back up. Meaning, the Edge has at least two other of this model of guitar and used those two guitars with greater frequency than this particular guitar. That said here is what the Edge told us of this guitar:
“Dallas found this one in Cincinnati and it became one of the backup instruments for my main 1976 reissue Explorer during the 1987 Joshua Tree world tour and many U2 tours since.”
Regarding confusion over the serial number, Gibson serial numbers pre-1977 serial numbers varied greatly. Many strategies were employed before the development of the system employed by Gibson today.
From 1975-1977 some experimental serial numbers were used. Please refer Blue Book of Electric Guitars Sixth Edition Gibson Serialization available in pdf form on the Gibson website. Where you can find the following information on page 4:
“During the period from 1975-1977 Gibson used a transfer that had eight digit numbers, the first two indicate the year, 99=1975, 00=1976 and 06=1977, the following six digits are in the 100000 to 200000 range. MADE IN USA were also included on the transfer and some models had LIMITED EDITION also applied. A few bolt on neck instruments had a date ink stamped on the heel area.
In 1977, Gibson first introduced the serialization method that is in practice today. This updated system utilizes an impressed eight digit numbering scheme that covers both serializing and dating functions. The pattern is as follows:
YDDDYPPP
YY is the production year
DDD is the day of the year
PPP is the plant designation and/or instrument rank.”
You can see why many would contend that this guitar’s serial number indicates that it was made in the year 2000. The idiosyncrasies of the serial numbers can cause confusion that we hope to have cleared up.