You might be able to see a version number in the html embedding code, though I believe it relates to the Player version the file is designed to play with. For instance, you might see something like the following included in the code...
Still, if it is a 10, you can be pretty sure it is a CS4 file, but if it is a 9, I couldn't say
That can not be right because when I try to play http://www.towerdefence.net/games-273-Azgard_Defense.php it only shows me the flash icon with a 9 on it. If you look at the code it reads...
<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,0,0" width="650" height="510" title="Azgard Defense">
You can uninstall the flash player and start with an old one and install newer and newer versions until it starts working.
The player is on an Archos 5 MP3 player and it supports Flash 9 and under but not 10.