Over here in the UK we didn't get the CR model so you will find all the UK Spec 900 Supersports be they the SS or SL had the alloy arms, although quite a few have ended up in the 600 and 620 race bikes.
May be worth contacting Baines racing I know they had one is their spares shed a while back
http://www.bainesracing.co.uk/contact-us.html