RhinoFish - 5:54 pm on Jul 8, 2012 (gmt 0)
when you have auto tagging URLs turned on, in AdWords, they add the gclid variable to the URL, so when the visitor lands, Analytics can tie it back to the google cpc, keyword, ad group, campaign, etc.
when you say you're worried it'll be "cached by Google", i assume you mean in their SEO index and SERPs - rest assured that Google's SEO team knows what the gclid parameter means and won't SEO it.
"there's no any variation on the page like meta robot Follow Index Or NoFollow NoIndex" -- your on webpages aren't using the gclid parameter to do anything dynamic, unless you intentionally programmed them to do so, or if the page / CMS is programmed to react to append data pairs in some defensive manner - but anyone who did such programming would surely be familiar with the gclid data pair. please repeat your test, which i assume is rendering a page on your site, with and without the appended gclid parameter, and reconfirm the page renders the same either way.