Don't try to adjust gap on iridium plugs. All you will do is damage the electrode thus ruining the plug. I have installed hundreds of these without ever checking gap. They are pre-gaped from the Denso and have a protective plastic collar to prevent the gap from being decreased during...
Checked with my local parts person at Toyota. 96761-24019 is what she gave me for it. Plenty on eBay.
http://www.ebay.com/itm/Inshino-Made-in-Japan-Water-Pipe-O-Ring-Set-of-2-fits-Toyota-Lexus-96761-24019-/252234491418?hash=item3aba58e61a:g:5MEAAOSwK7FWhvK5&vxp=mtr
Dealerships should keep...