If you know the default prefixes for the various alt-coins (e.g., btc, ltc, wdc and mnc addresses usually start with "1", "L", "W" and "N", respectively) you can just open up the .dat file in a text editor (notepad, notepad++, etc.) and look for the addresses in there.  I think that you can find the addresses by searching (ctrl+f) for the text string "name" and a bunch of addresses should be listed near that.  Then it's just a matter of figuring out what cryptocoin the wallet belongs to depending on the first character of the address. Good luck!