August 2 for Polk Dollar, only release "time" I can find for 3rd Lincoln is "Summer".
see here for Polk: http:http://www.usmint.gov/mint_programs/$1coin/?action=schedule
re the Lincolns, if you know when the 2nd ones were released, you might be able to guesstimate by addding 3 months:
This is from the US Mint site:"
The new one-cent reverse designs will be issued at approximately three-month intervals throughout 2009. US Mint - 2009 Scheduled Products Listinghttp://catalog.usmint.gov/webapp/wcs/stores/servlet/ProdschedView?storeId=10001&catalogId=10001