Just had share the experience. I bought this rig, a 1970 white sparkle T&R Kustom 200B1 with the matching 2x15 cab last week. It was labeled as CTS speakers, but actually had a real sweet pair of period 16 ohm Fender signature JBL D140F-6 speakers, with the orange and silver decal. Thrashed around this week replacing the worn out wheels and handle inserts, as well as going through the entire enclosure along with locating the nut that holds the speaker jack in place. Finished just in time to take to Friday night's gig subbing on bass. I used a newer Kustom KBA500 head and a 90's reissue Danelectro Longhorn with the original flats on it. Amazing!
Ended up with one of the elusive tones that we all search for with plenty of volume as well. All of the other guys in the band immediately told me how good the bass sounded. My first experience with the JBL D140F-6 was quite the trip.
BTW - the JBL's are original. Never been rebuilt or reconed!