SP1 was preinstalled in the OS image. SP1 shows up under computere/properties as well. And, just to be on the safe side, I dug up the SP1 x64 image I have archived and it verified that SP1 is already installed.
BTW, MS must have removed x64 SP1. The link you post serves up x86, even though the catalog shows it as x64.
**One thing that may be a factor is that I removed the telemetry updates before integrating SP1 into the OS image. I may compile a list of the updates left out and install them to see if it makes a difference, assuming those updates are still available.
Problem solved. I decided to call support again (the first time the guy said he had to connect to my network...that there was no other option, to which I objected). This 2nd rep sent me links to downlod the full programs directly (1.5GB each!). I was able to download them and get them up and running.
Thanks to all who contributed. Much appreciated.