Ok, so as promised, I installed the 64 bit Windows 4.1.5 w/ JRE on top of my existing Openfire 4.1.4 that was already running 64 bit thanks to the patched files floating around here and the 64 bit JVM, but was located in the Program Files(x86) folder.
Upon starting the installer, it of course did not detect the existing installation because it was looking in the Program Files rather than Program Files(x86) folder. I stopped the service and copied the OpenFire folder to Program Files, and then restarted the installer and it detected the existing Openfire installation and proceeded to run normally.
After the installer exited, I deleted the existing Openfire service and installed the new service from the new installation, so it now references C:\Program Files\Openfire\Bin\openfire-service.exe, started up, everything works fine.
Now for the odd bits.
Version still says 4.1.4 even though the installer said 4.1.5
Something still needs/wants the Openfire directory in Program Files(x86), because when I tried to delete it, it would not. I stopped the service, deleted the old directory in Program Files(x86) and Openfire would no longer start up.