No, I am not referring to the Mason-Dixon Line
I have polished and restored a number of katars over the years, all antiques. There seem to be two major types, based on their configuration and decoration. What I call northern appear to be associated with the Persianized, Islamic culture of the Mughals. The weapons tend to have wootz blades, and the surface decoration tends towards gold or silver koftgari on the sidebars and grips. When suspended by their grips and struck with a mallet or similar object, many of these emit a beautiful, clear ringing sound. Without ever having the chance to Xray or Magnaflux one of these to verify, I TEND TO BELIEVE FROM THIS OBSERVATION that they may be of one piece construction (insofar as the blade / sidebar assembly goes).
What I call southern types have a mode of construction and decoration which parallels the sword types of the older, Hindu cultural stratum of India. Their blades are often rivetted between a pair of langets or projections from the hilt assembly, which is typically decorated with deep chiselling or a filigree-type openwork. Blades on these katars are sometimes of wootz, but more often than not are plain crucible steel and occasionally a folded laminate of hard and soft materials, much like most Far Eastern blades are constructed.
I admit that my labelling the two types "northern" and "southern" may be disputed from a strictly ethnographic standpoint, but since the Persized Mughal culture was strongest in northern India, I use this dichotomy here simply for the sake of convenience.