Jango's darts appear to be the squared off shoulder design with a single groove near the tip.
Boba's darts appear to be the radiused or 45 degree shoulder with double grooves.
Can both types be done?
I would be interested in a set of Jango darts in a couple months.
I have gone through every picture I can get my hands on and the "groves" in the head of the darts are screw threads. It does looks like they have either been filed down to soften the edges or it is an accumulation of paint that has filled them in. It was a surprise to me as well. But I have come to expect it from Fett.