Hey heyyyyyy.  That sounds like a bit of a legal issue.  But a new replica from 2014?  Lets see some pictures of this thing!  All the old school quadracers are LT500R or LT250R.

The octane of the gas would depend on how the engine was set up.  It could be a higher compression build that needs high octane fuel.  I suggest doing a compression check, then you will know what octane fuel is needed.  It could also be that the timing has been advanced and that requires higher octane fuel too. 

I was out in Vegas exactly a year ago.  Good times haha.