Not totally up to speed with KO rubbers but
just put my K2 together and if they are the same i just put a wipe of washing up liquid around them and a light tap with a rubber mallet.
You need to get the orientation right ie. cylinder numbers at the top (if they have them on yours)
then carbs on and then airbox and inlet rubbers.
My airbox to carb rubbers needed replacing as when assembled were too short,had shrunk over the years, new ones were 5mm longer,
Hope this helps
Rich