if this adds anything to what was said before about the suicide shifter, i looked it up and i do not think there was a suicide shifter originally, but there could have been. the attached front derailleur shifter that i got with the bike was completely different from the mounted rear derailleur shifter, thus there could have originally been a suicide shifter and possibly neither of the shifters that came with the bike are originals.

also, i came across this picture:

although not in use, my bike does have 2 housing points for 2 cables for the rear derailleur like the bike pictured above. i dont know if that helps.