Glass question?  

Yes
in a word x

*
Many thanks, Robert. I need to return to Florida in 3 weeks, as the local glass company is replacing all of my glass windows and doors (with impact resistant). They are also replacing the nasty beveled mirrors behind the living room sofa. Perhaps I can send the top back to their shop with the installers. I will ask.
All the best,
Aunt Mark

Tempered glass
As for as I know the top of a Barcelona table is tempered glass for safety reasons.
Cutting tempered glass is very tricky as it can shatter in a thousand pieces. So be sure the glass company is well qualified in processing and reheating tempered glass.

Thanks you, vintage.
So, any idea how to tell if it's tempered or distempered? I appreciate your feedback.
Aunt Mark

Recognizing tempered glass without an applied stamp is nearly impossible.
But tempered glass is a standard safety measure for quality table tops. If an accident happens it will shatter in a thousand small pieces that will do no harm instead of large dangerous sharp shards.
Your glass company must be able to reheat the glass to make it processable.

Many thanks again, vintage.
I shall quiz the glass company to see if shaving off a tad bit is possible on this (whatever) type of glass. I am learning something new on this forum every day.
Best,
Aunt Mark

Any
Any bevelling would be post-production, so grinding off the edge shouldn't be a problem either, in competent hands.

wouldn't a nick in tempered glass
shatter the whole top? That has been my experience. It stays whole or in a million pieces. No in between.

Goodness leif,
My glass top to has 2 slight nicks, and no shattering yet. I wouldn't mind if it did shatter..as it would be an excuse to buy a new table. I wouldn't buy another Barcelona table, as the sharp corners make my legs bleed (which is not acceptable in my neighborhood).
Let's have a drink...order up.
Aunt Mark

Mark
I would go straight to Knoll for your table's glass specs first. Not all tempered glass is the same. Once you know what type of tempered glass it is, any good glass company should be able to work with you. If it were me, I would also ask Knoll et al how much a replacement top would run as repairing a glass top sometimes can cost as much, if not more, than a new replacement. (just in case you decide to keep your table in spite of the sharp corners.) In my view, the Barcelona is one of the most beautiful tables going.

Possible mirror choice
Mark, If you decide to take down the mirrored wall and install hanging mirrors instead in order to open your space (a preferred choice in my opinion), the Casamilano square Specchio mirror would be a nice choice with your Barcelona table. Depending upon how wide your wall is, you may need two side by side. I have one over my bedroom's chest of drawers and it is a wonderful mirror with Mies period MCM.
Also, removing glass from walls is best done by the professionals.

Polarized lenses, even...
Polarized lenses, even Polaroid sunglasses can be used to see the stress patterns in tempered glass. There are a coule easy methods, some easier depending on the item. Web search for how.