Found this online, don't know how correct it is though.
All HW is shipped with the enlarged closure these days..
To see what you've got, grab a nickel and a dime.. If the hole for the nozzle
is the size of a dime, it's the Standard (old) but if it's the size of a nickel,
it's the enlarged (new). The enlarged should work with all current reloads...
Regular closures should have a hole just over 5/8" diameter, large hole
closures just over 13/16" (About .635" and .820")
I don't have the motor yet, I'm gonna get it from Ken next time I'm in Camden. I was actually hoping you might observe me assembling the motor before my L2 cert flight???? Any chance of talking you into that happening???