This is a myth. The Win32 API doesn’t even have a method that returns the string “Windows 95”! Windows version numbers are numbers, not strings. Windows 95 was actually 4.0. Windows 98 was 4.1, ME was 4.5, and XP was 5.0.
Actually it’s not entirely a myth - there was some Java library that did this - but it wasn’t widespread at all, and certainly not the documented approach to check the version.