With Bitcoin Core v0.15.1, the old wallet.dat files I could try each of them by copying wallet.dat to this directory?

C:\Users\{user name}\AppData\Roaming\Bitcoin

I did this with one of them and some how my wallet went from one key that was 16k to 2400 keys with a size of 2400k.  But it has not synced yet so balance is 0.  When I dump keys with pywallet they do not look like bitcoin addresses though.  They look like sha64?

Rather than waiting weeks for this thing to sync, could I copy each of these addresses to blockchain info and I think it is called sweep to determine the balance?