65 shimmy, bad knuckle

I just bought a 96 miata for 1900 off of ebay. It runs very good except for a random miss and a shimmy at 65. I had thought the shimmy might be due to a poor balance job, I recently put new tires on it, but when we put it up on the lift we found the drivers side rear knuckle to be loose. The tire has play if you grip it at 9 oclock and 3 oclock and shake it.

I work at a Honda dealership and get parts at discount as well as labor at $10 an hour. They are telling me that, If I can get a new bushing for the upper arm, and if the bushing there can be pressed out, then thats the way to go. Otherwise Im going to need to replace the entire knuckle.

Anyone have input on this? Im not knowledgable on suspension, so am not sure Im even using the correct terminology.

The bushing can be pressed out. Most people have done this to upgrade to stiffer bushings.