Manual Trans Guru's- odd synchro ring question
 

Odd question, but basically need some dimensions.
I have an old Nissan Compitition 5 speed transmission that uses steel servo synchros. The synchro rings are NLA from Nissan anymore. However, some research led to some rumors that they are a Porsche part. Reading another thread here..
http://forums.pelicanparts.com/4279865-post6.html
it sounds like there are two basic sizes of these rings which you can distinguish by the diameter. I had my trans guy measure the installed/compressed diameter and it fell inline with the 78mm diameter version. So I ordered part number 91130230108.
I dropped it off to him a few days ago and he called today. The diameter lines up, but, the width is off. The ones in my trans are 8.5mm wide and the one I provided is 7.5mm wide.
Is there a synchro ring that is 78mm diameter and ~8.5mm wide? It's hard to find info on the dimensions of any of them. So I'm hoping someone knows the difference or has extra's handy they can measure and tell me.
Any info would be useful!

Thanks!