Yes, download it from Apple, close all browsers and other programs, run the installer, reboot, or shut down and resart, hold down the shift key if you have DellEFI 1.2 alpha 5 or -x for the others to safe boot, enter your password, re run DellEFI, custom install, etc. from the guide.
If you have a USB thumb drive, you can make a back up using Carbon Copy Cloner. Not a bad idea to have a back up just in case, but it should go smoothly.
I would do it, since you have everything working properly now.