If you have updated to macOS Mojave 10.14.1, or applied the latest Security Update for High Sierra (2018-002) or Sierra (2018-005), you will have noticed that your EFI firmware version has not only changed, but the format of the version number is now completely different.
Instead of the old numbering system which looked like
0220 B00, these updates introduce numbers like 188.8.131.52.0. This is to be expected (it had been reported in betas), and I think should apply to all Macs to which these updates have been applied.
I will later today check through the new version numbers, and post a new list of EFI firmware versions here. For the moment, if your Mac’s EFI firmware version has changed to the new format, you can be confident that it is now running the latest version. If it hasn’t, wait for my new list before starting to panic!