Type info:domanname and google it. If the domain is forged, the original domain will appear. You can also check it this way. cache:domainname. Hope this helps!
I think installing Google toolbar will help you for checking PR. If the site is showing fake PR then check it in PR checking tools.
I am agree with the above webmaster views but i think you can check page rank by Google page rank toolbars..It is the better options...
By using Pagerank in the toolbar or you can choose any pagerank checker to know if such site has fake or forged site...
Add web rank toolbar in your firefox browser it will show you page rank also submitted link in Google,yahoo also backlinks in alexa, bing, google,yahoo.
I have some more powerful tools. Check them.... http://www.seoranksmart.com/tools/webmaster-tools.htm among all I like Bulk OBL Checker and Bulk Page Rank Checker the most
Its best firefox ad-one to see your site PR.Name is seo search status. https://addons.mozilla.org/en-US/firefox/addon/321
many way to check fake page rank like type domain name in search engine and put website url in online tools which can be saw you website page value