His widow Martha filed for a widows pension in 1831 and gave an account of his service, birth dates of the family including children. There are sworn statements of others attesting to service and marriage. Robert Parks was a "Junior" b. August 24, 1748, Martha's maiden name looks to be Grant. Death information is the same as you have. The original papers have been scanned from the NARA microfilm and are in a database titled "Revolutionary War Pension and Bounty-Land Warrant Application Files, 1800-1900" at Ancestry.com, a subscription genealogy site. If you don't want to subscribe see if a LDS Family History Center has it or your local library. With the cursive hand writing it is best to see the original scans so one can magnify the image for transcribing. Original source data is: "Revolutionary War Pension and Bounty-Land Warrant Application Files (NARA microfilm publication M804, 2,670 rolls). Records of the Department of Veterans Affairs, Record Group 15. National Archives, Washington, D.C."