I want to keep my PPC landing pages out the organic index but let Adsbot-Google find the page. Will this meta tag work?
<meta content="NOINDEX, FOLLOW" name="ROBOTS">
I generally use robots.txt files to set up my indexing rules
You can block PPC pages from all indexing while allowing indexing of the rest of your site:
And then make an exception for adsbot-google for the same pages/directory
You have to make sure you grant access to Adsbot-Google or your ads will not run.
Webmaster Tools is a great place to work on/create a robots.txt file.
I know this doesn't address your question directly but it is an alternative that you can employ to achieve the same result.
Here is more information about using meta tags how you have outlined.