According to www.analogman.com:
"In about 1993, Ibanez started to make the TS-9 again due to popular demand. This "reissue" is just about identical to the last "original" TS-9s in sound, circuitry, and appearance. The IC chip they use in the reissue is the same as some later original TS-9s, the Toshiba TA75558. They are a higher tech chip that will work good in higher tech equipment (where you want a low noise op amp) but are not the best for a tube screamer. If you want some of these chips I have a few hundred slightly used ones! ;-)
In about June of '96 the reissue TS-9 was changed slightly, and finally can be told from an "original" TS-9 easily. There is a "CE" symbol on the back, which is required for selling electronics in Europe. Also a capacitor was added to the back of the board (the only component ever used on the back of a tube screamer board). This is to help with the switching circuit and should not affect the sound. The extra capacitor is no longer used, now they changed the value of C113 from 102 to 103 (10,000pF). C113 is between the wires labeled 3 and 4 on the back of the board. If you have a 102 you can change it to 103 to improve switching (switching is the one thing about TS-9s that sucks!). I think the new TS-9 sounds the same as the earlier reissues and last originals. "
I've got (2) reissues and (1) of the original TS-9s, and they really do look nearly identical. Of course, the biggest difference is that the original has a couple of dings/scratches and the reissues do not
Aside from serial numbers, the early reissues are VERY similar to the originals, and aren't easily differentiated by the untrained eye.