Thanks for the reply. Sounds like having my dad provide his dna is the best route to go. I can always send in my own at a later date to find out stuff about my mom's side. We can trace that side back past my great grandparents, so we know, to a certain extent, where our ancestors came from.
My dad's mom's side is the only history I don't know anything about. I know her original pre-adoption name, but the last name (Pond) matches her mom's on the adoption paperwork, which means she wasn't given the father's last name. Hopefully, once we get the original adoption papers, we can figure out if the Marion Pond I found in a family tree on this site is same Marion Pond as my grandmother. There's already some convincing evidence, and maybe the dna testing will be able to help confirm that in case the adoption papers don't help.
Really hoping the dna testing will at least give me some leads for finding my great grandfather, and it sounds somewhat promising. Anything's worth trying at this point I guess. Worst case scenario is that I may not get a name, but I'll at least get an idea of where that side of the family came from. Thanks again.