The beautiful McCarty Ziz made for his CA100 came to mind when I saw this very rare setup on a good-looking pre-Guild ancestor, the 1945 Epiphone Broadway.
http://letstalkguild.com/phpBB2/viewtopic.php?f=3&t=29364&p=317601&hilit=McCarty#p317601
Original thread here:
Epiphone R-1 Spectrum double pickup cutaway pickguard assembly, with screw-on mini-connector cable, adjustable hex-key truss rod under fingerboard.
In June of 1948, Gibson debuted a "Finger Rest Pickup" on an L-7 model at the NAMM music industry trade show. This unit, now known as the "McCarty" pickup after Gibson's chief engineer, incorporated one or two floating P-90 pickups into a custom pickguard designed to convert acoustic archtops for electric play. Around the same time, one of the Epiphone partners, Frixo, designed a double floating pickguard pickup system for his own '47 Emperor, using a pair of Epi "Tone Spectrum" single coil pickups.
By November of 1950, the Epiphone conversion pickup was listed in the company's price list as the "Epiphone Spectrum Pickup in Pickguard Unit" and came in single and double versions, for cutaway or non-cutaway guitars. Like the McCarty, the Spectrum could be ordered as a factory option on a new guitar, or added as an aftermarket part. The McCarty pickup remained in Gibson's catalog until 1970, and was a popular option for their carved top guitars. The Spectrum pickup, by contrast, is now so rare that even the most diligent collectors have never even seen one, much less had the opportunity to play one of the fabled units. http://www.archtop.com/ac_45bwy_911.html
http://letstalkguild.com/phpBB2/viewtopic.php?f=3&t=29364&p=317601&hilit=McCarty#p317601