850 mk1 interstate

Hi all havent been on since i joined a while back. At the time i was considering a norton then ended up having a shoulder reco so things been on hold. Anyway there is the possibility of the bike above. My mates commando which i decided i wanted was sold before my procratinating stopped. Mind he did some work on this one and said it is probably better.
So really i am after help as to what to look for. My mate said that it is still on the original bore with new rings. I presume this was done when leaded fuel disapeared and the head was done. Apparently the speedo needs fixing but otherwise ok hasnt been used a lot. I decide that a runner with a good motor is the way to go. I have a new bonny so i know the obvious things, tyres, chains, sprockets etc. Are isolastics hard to check or do you just adjust them?
As an aside and i dont want to start any arguments but how do you thnk a commando and new bonnie would compare performance wise?
Any advice greatly appreciated.

A good Mk1 850 is pretty damn quick, I reckon it might show your Bonnie a clean pair of heels. As standard it would have shimmed ISOs a bit of a pain to set but not difficult, however, there are kits available to up grade them to the Mk3 style.

Cash