[HO455]

Throttle shaft bushings on a new Qjet (NOS) will allow the shaft to wiggle. 002 to .004. As the carburetor goes through it's life the base plate holes will wear as will the throttle shaft. An extremely worn carburetor will have 3/16 of fore and aft play in the shaft.
The majority of the wear occurs in the base plate due to it being a softer material than the steel throttle shaft. The result being that when new bushings are installed there may be play than in a brand new carburetor due to the wear on the throttle shaft. This additional play would be measured in thousands of an inch not fractions of an inch. I speculate that you are feeling this amount of play and it should not be a problem.
This small amount of play is allowing a small amount of air into the intake below the carburetor metering circuits. This type of air leakage was designed to be compensated by the idle mixture screws. Thus over the designed life span of vehicle proper idle characteristics could be maintained.
Can you give us a measurement of the play you can feel? The average human can easlly detect .010 of play but, most don't know how to communicate that amount. I suggest you compare the amount of play you have to a feeler guage and let us know your findings.