Anne, check with your county veterans office, My understanding is anytime after you file a claim, you can add any material you find after to support your claim. Also after 6 months of filing, the VA normally will send a follow up letter asking you to submit any new info you may have gathered. On buddy letters be sure your buddy person has something to back up his letter, as anyone can write a letter and say anything. VA looking for some kind of support to prove the buddy letter info is true.