No, actually, 'shellac' is a resin that has existed for ages. 'Shellac is a resin secreted by the female lac bug, on trees in the forests of India and Thailand... Shellac functions as a tough natural primer, sanding sealant, tannin-blocker, odour-blocker, stain, and high-gloss varnish.'- source, wikipedia.
So, if any company uses 'shellac' in their ingredients in the salon industry, it can be called shellac. Shellac is not a 'brand name' by any means. So, it will be very difficult for any company to get a registration on that name because you can imagine how many office actions they may have about it becoming a registration. I think that if CND were allowed to put 'R' behind that name, you should then say it is 'their brand'... however, it's not and other companies have used shellac in their gel formulas, so, it is simply a way of rebranding a high graded gel which has shellac in it. If they don't have shellac in it, using that name would be a bit of a con. So, it must have shellac in it, etc. Also, if a company has filed the name 'shellac' and declared their use of that name as a trademark application for registration, they must do so by territory (for example, if you register a name in the United states, it doesn't mean that you have that trademark world-wide, you actually have to file application to register that name in every country). And you can put 'TM' behind any name you use even if you haven't filed for registration. But, you cannot put 'R' behind the name unless it has the application has been accepted by the examiner, etc. Hope this clears things up a bit.