I think all the early round body carb'ed engines, were a single carb.
in 88, 89, and 90, there was only an SP for a 2 seater. The XP didn't come out intil 91. (with twin carbs)
the GT (3 seater) came out in 90... and it may have been a twin carb.
You should have a single BN38 on your Doo.
If you need one, I have one on the shelf. Used, but clean, and ready to go. (PM me) I took it off, and swapped a Super BN38 in it's place. (They have a built in fuel pump)