Indeed that is the spacer !!
Your 5th Gear Casing photo also confirms that the original Renault 5th Gear Plunger and spring has been removed, (which is what we now all know)
Anybody on the forum got any comments regarding the burring on the spacer?? (I believe this may be attributable to incorrect shimming of the driver shaft yokes but I would be interested to hear other opinions.)
Kindly PM me details of what you need to post the spacer Joji, (I can Paypal this to you or other), kindly PM me with details.