No, Win32 is case-insensitive. It's traditional on Windows to use upper-case, but it doesn't matter.
NTFS is actually capable of behaving in a case-sensitive manner, but Win32 is explicitly case-insensitive. This leads to weirdness if you don't use the Win32 subsystem and create a file whose name differs from another only by case, then try to open them using a Win32 program like Notepad...
Thanks for the info! Now on with trying to figure out why the ip's still aren't blocked in modern apps...