2000 Es300 - Sway Bar Bushing Size?

[ml30306]

I own a 2000 ES300, ca. 133k miles. The front sway bar bushings have gone bad - there is a strong creaking sound when you push down the front, first thought it was the struts, an independent Lexus Shop stated it was the sway bar bushings today.

Moog makes 2 sets for the front - K90393 titled 18 mm and K90394 19 mm. All parts websites state these as fitting my vehicle. Question - What does the 18/19 mm refer to - the sway bar diameter? How would I go about finding out which size fits my car? 1 mm is not a lot in general but in the bushing world a lot.

Would appreciate any advice/comments - thanks!