I'll reply here since its more relevant - with my bad front MC, I just replaced it out right. For the rear, I was toying with rebuilding it and I had the same conundrum as you. Do I spend 37x rs for a rebuild kit or get a new one? I just opted to get a new one. Surprisingly, new rear MC, with the reservoir and hose was 650rs from the KTM showroom, as opposed to 750 for just the rear MC alone from bajaj. paying < 300 for all fresh parts was absolutely worth it IMO.
The new front MC from KTM was 30xx rs, with the adjustable brake lever itself costing 19xx rs. I should have bought the Duke 250 version which came with the regular levers and the same MC but it worked out well as I got the adjustable clutch lever too.