The registry key was there and I did delete it. However, even after rebooting I had the same error. I was actually trying the legacy as a troubleshooting step. I had used the online configurator previously successfully (and as a side note, I just tried it now and it works with the online configurator) but when I combined the online configurator with the Standard MSI Package option my Windows 10 computers gave an error about the digital signature after installation. Rebooting the PC got rid of the error and everything was fine but I'm trying to streamline this so I can push out the MSI through GPOs in Active Directory (like I did previously). I had used the One-Click or Agent Package (I forget which) for pushing out through Active Directory previously but chose the Standard MSI for some updated settings since it mentioned specifically deploying via AD.
I guess really I could just choose the One Click and see if I still get the signature error. I just hadn't seen it before.