Mikuni BN40-38-28 vs Mikuni BN40-38-24

[ctys20]

I found a good deal on a Mikuni BN40-38-24 and the seller says it's the same as the "28" and will work in my boat (98 sportster with two 717's)? If I recall correctly the last digits = jet sizes?? So if the jet sizes are different would tuning be a problem? Just want to confirm with someone who has done this before. Thanks!!