Pant defines Gaddara as a yelman-ed sword with a triangular point ( see attached pic from his book). He attributes the origin of the name to "gadar" : engaging in riot, mutiny.
I also show the so-called Irani Gaddara, with a typical Persian/Polish Karabela-type handle, all steel. The blade has incised panels on both sides, with remnants of gilding.
Indian swords with a double-edge segment at the tip are, IMHO, descendants of Kalachoori and you may wish to look at the very end of the thread
http://www.vikingsword.com/vb/showthread.php?t=4223
where Odevan and myself are trying to come up with the origins of that name.