Yes the metal sleeve is still on the carb.No worries there...the problem is a minimal movement barely noticeable but it is there.
More noticeable when installed on the car and hitting throttle/brake!!
As for the venturies, i personally remove it or use a 9mm, i can not imagine the 3 port R with 6 or 7 mm venturies.
How do you get this thing moving with the 6 or 7?
It already lacks the power down low so an even smaller ventury would theoretically kill it!