I have never seen an Evo without the primary gear mounted with rubber dampers, factory or standard. I know that there are aftermarket clutch systems without the rubber dampers.
2 thoughts 1) with the fuel turned on and the bike laying flat on the ground ( either side ) does fuel pour out onto the ground ?
2) have you taken the flywheel off the check the woodruff key ?
IRIS 520 RXL chain, 1/2 links and master links readily available in the USA I would purchase 1 x chain 106 link 1 x 1 and 1/2 link and 3 extra master links