How to identify early '82 carbs from late '82 carbs

There are two versions of the 1982 Vision carb, an early version and a late version.
These changes seem to coincide with the mid year addition of the air box flapper, BUT it seems, in many cases this seems Not to hold true.
Do not assume that because you have the vacume operated flapper you have the later model carb. 

The simplest way to tell the difference between the two carbs is the addition of a stop screw on the accelerator pump linkage.  The reasons for the changes were obviously to cure the carb related performance problems that plagued the bike early on.  What other changes were made I cannot say, as I don't have a late 82 carb to compare with, but most likley, fuel metering & delivery was the focus. 
It is worth noting that the 1983 carb is a completely different animal, and only a  few parts are interchangable with '82 carbs.

Early 82 WITHOUT stop screw

Early 82 WITH stop screw