Yes mikey you will ned a new head gasket.
On the side of the engine will be a decal with the * sicker actually ) with the family and serial numbers on it.
You should make note of these because the decal will eventually fade or fall off.
With those numbers in hand ( you can check here first to make sure they are correct ) you can go to Kohlers web page, customer support & download engine service manual and for some the parts manual as well.
If not then any of the majr on line parts suppliers ( including Kohler themselves ) will have a parts breakdown with the head gasket number on it,
But before we go putting the cart before the horse,
Did you dip the oil & was it too full, thin & smelling like fuel ?