The driver was installed (and then updated to the newer version) through a custom installer, rather than directly with an .inf file. (Manufacturers love plastering their logos everywhere.) Whoever developed the installer, assigned different product codes for different versions, resulting in two "Uninstall" entries even though the old files have been replaced with new ones. Normally, installers use the same product code for the entire life of a program, so that its "Uninstall" entry will be re-used on upgrades. Unfortunately, not all programs have such good manners.
If this is the case, your system only has one version – the latest – and attempting to uninstall old versions would actually remove the driver or program completely. You can find out whether this applies to your driver or not by diving into Registry and checking if the two entries point to separate uninstall programs or the same one; the same way you can remove extra entries (by carefully deleting the relevant key (folder)).