An e-mail from The Geek with an update...
"Apparently the stain is normal and will fade with exposure to light and air. It's part of being Marmoleum - he even had a pamphlet for me with details.
Roland, the installer, will likely be back tomorrow to put the stuff in.
And we got a big thing of Toblerone out of the deal.
The rep also told me that they are using this stuff in the new airport and the new addition to the VGH."
I have my fingers crossed.