At least three versions, actually: the original release of 10.14.6, then the first Supplemental Update, and now this re-released Supplemental Update!So now we have two versions of 10.14.6! The 'old' combo update and the 'new' combo update. With a new combo update it really should be called 10.14.7.
Because I want to keep the latest Mojave installer around to use (say, in a virtual machine) for running 32-bit software, I have within the past few weeks downloaded three different versions of Install macOS Mojave: 14.6.02 (after the initial 10.14.6 release), 14.6.03 (after the first Supplemental Update), and now 14.6.04.
I agree that the macOS version numbering is unrevealing when it comes to builds: the easiest way at presest to tell at a glance what version of macOS a machine has is to click on the version number in About This Mac and then compare the build number that appears to some known value. (One can also click on “Sofware” in System Information.)
Apple’s version numbering for the Mojave installers suggests that this macOS build might properly be called 10.14.6.04, but clearly Apple think we should just trust Software Update to automatically check for updates and not worry about build numbers.