Obviously they don't make a factory kit for the L2, nor do they for any Gleaner for that matter.  (Don't know if they will soon or not since mother AGCO has the reins).  In any case it comes down to how wide your clean grain elevator is.  The flow sensor and chain could be installed if it will accomodate their smallest width chain, the 8 tooth.

You'll have to install a moisture sensor too but that is a giant question mark as the retrofit one they have is made for Deere or Case only.  Bottom line is, it can be done with any machine but there'd be a lot of time, money and cussing involved to get there.  By the time you spent all the money you'd have as much into the system as buying a used weigh wagon and a Dickey John Mini GAC and you'd have the same thing.