Unfortunately... I don't think you can't know. I had this problem because I saved a bunch of different wallet.dat from old coins that I was mining in the early days when I was learning how to mine (so I used low difficulty altcoins that I could mine with a GPU) and ended up with a bunch wallet.dat
When you put a wallet.dat of LTC in Bitcoin Core's folder for example, strange things happen, your funds actually show up ar least they used to, but it was a glitch.
So you will need to remember what coins you had and test them out until you find what is what. Next time make a folder for each separate wallet.dat with the name of the coin that it belongs to.