if I remember well when I installed mine, I think one is the old version and the other is the new version of the cruise control.
the 2877177 is the old I think.
when I ordered it I received the old version and it didn't fit my 2014 HB.
though, if the new version fits your kingpin I would go for it. it's better against water etc.
reconfirm with Polaris this, I get easily confused with the part numbers. and make sure to mention you want it black or chrome. I think the old is chrome and the new is black anyway.
2014 Victory HighBall