Examine the “Genealogy and Military Records” page on the National Archives page. (Non-U.S. folks: examine the military records information from your country’s national archives.) Click the links and read everything you can. If you’ve ordered a military file before, read this page again and refresh you memory so you can help others. Authors of genealogy blogs can write about records they’ve received, comment on the National Archives page, or ask questions of their readers via their blog.
I have written to the National Archives requesting military records in the past. I wrote about it in this post. I've also requested military documents for one of my Dad's brothers and did receive a reply but no medals. Medals are reissued to next-of-kin. My Uncle never married, had no children, his parents and both brothers are deceased. They would not recognize me as next-of-kin though.
I do need to spend more time on the site looking at the images and seeing what information I can find for the Mexican Expedition. My grandfather served in the Army during the Expedition but I have had little success finding information. What information I did find was from a book published by his fraternity that talked about "their brother's on the border".
I get lost very easily on the NARA site, but that's not a bad thing. The things I find while lost are always interesting! The volume of information is unimaginable and the thought of even a 1/4 of that information being digitized is a great dream!