About this Mac/SMBIOS issues - Serial Number Unavailable and no Mac model #

I'm working through updating my opencore config and I'm struggling to get the smbios to work.

Issue:

• About this Mac and System Profile does not display correct information
• I haven't attempted to sign into iServices, yet.

Details:

• OpenCore v0.7.0
• config.plist - Link - passes OpenCore config.plist Sanity Checker for 0.66
• MacOS Big Sur - 11.4 & 11.3

Specs:

• Motherboard: Gigabyte Z390 M Gaming
• CPU: Intel Core i5-9600K Coffee Lake
• GPU: PowerColor Radeon RX 5700 XT
• 1x Nvme drive

Process:

• Download OpenCore
• Started with clean sample.plist
• Followed these instructions for MAC/ROM: link
• Generated new smbios - this tutorial: Link
  
• Converted to USBToolBox and removed USBInjectAll

Things I've tried:

• clear nvram via OpenCore bootloader
• I've tried both iMac19,1 and iMac19,2.
• rebuilding from a clean sample.plist

I've hit a troubleshooting wall and I'm looking for suggestions on what to try next.

Thanks for any tips.