Do I have to re-balance this 360

if you are OK with the 360 being previously balanced then you could weigh the new pistons/pins/rings/locks (if used) against the old heavier piston/pin/rings then order some heavier pins to get back to the same weight WO (re) balancing & iirc 273 pins were deliberately made very heavy to do this exact same thing at the factory for interchange purposes. HF has an accurate gram scale for cheap. do your homework/Google & see what develops