I know exactly who you need to contact regarding the burial locations for the two brothers. His name is Tom Holley and lives not far from me. He wrote the book on the Ramsey Volunteers. It is very possible, I guess, that they are buried in the Magruder cemetery as there are a few graves that are unmarked. It would be very hard to positively find that out for sure though. Their brother, Oswell C. Magruder does have a marker and was supossedly a Confederate Soldier but I have been unable to identify his unit.
On another note, the Magruder Family Cemetery is in my "backyard." I just recently purchased the Magruder house (last week actually) and although it will take a lot of work (and money) I look forward to maintaining it.
I welcome any and all Magruder descendants to come by anytime. And if there are any pictures of any of the old Magruder family members, I would love to get a copy to place in the house.