AFAIK, the actual color was highly dependent on the hardware used (e.g. video adapter, CRT, etc.). That's why photographs of a Windows 1.0 screen might look vastly different.

The color I listed is what Windows outputs on the software side. It's pretty much an EGA dither of bright cyan and bright green. It's what you would get with todays hardware.

Interestingly, none of the screenshots I can find show the dithering that the article talks about, and all the contemporary photographs of monitors show a less green blue background. I think maybe something is being lost in emulation?

It probably looked much less neon bright on the displays of the time. Same for Windows 2.0.