EDIT - I finally got it working, but I don't really know how. I rebooted the computer and after the entire blockchain synced my old balance showed up. Had I known what to expect I wouldn't have gotten so vexed, however.
Do you know how blockchain works?
Your coins don't store in the independent file, they don't exist at all. But blockchain - it's all transaction between all adresses. So when it made full sync, you can see you ballance.
Be happy and have a nice day//
Haha, very funny. In restrospect this is precisely the behavior I should have expected, yes. But consider the confluence of factors here: I installed a new wallet; it did not appear to automatically recognize my existing keystore; it also prompted me to either import an old account or create a new one, but selecting import appeared to do both, while also zeroing out the old account; there was no message about syncing the blockchain and the old 0.7 wallet did not show your wallet balance until it was done. The last issue was the complicating factor here - something funky happened with ethernet connectivity with the one port on the switch this computer was connected to and I ended up having to cycle power to the switch and the router to fix it. Frankly, I've never seen just one port stop working so learn something new - usually unpleasant - every day, I guess.