What class of refit would it be to replace two Light PPCs (in the same location) with a Snub-Nose PPC? Class A uses the singular "one weapon":
replace one weapon with another of the same category and with the same (or fewer) critical spaces (including ammunition).
...but Class B, while allowing multiple weapons as part of the swap, is focused on changing class, which this would not be:
This kit allows replacement of one category of weapon with another class of weapon(s), but with the same or fewer critical spaces (including ammunition)
Since it seems to fall at about "A-and-a-half," I thought I'd ask. A search turned up this thread:
http://bg.battletech.com/forums/index.php?topic=5271 in which a similar question was left unanswered.