Any way to customize the RH Server login screen?

All-

Continued tests of the RH Server seems to show that when someone (say, a customer who's interested in accessing content) attempts to access a protected site, they are presented with the standard RHS Admin login screen:

I'm interested to know:

1. If this is in fact the default screen a customer (content consumer) would see, and
2. If there's a way to customize this image.

Colum's response to the discussion here:

customize robohelp server web admin

Seems to indicate that customization is NOT possible (tho the thread is 4 years old.)

Thanks!