Yes, the symbols are the IP of ISO and are copyrighted. To reproduce the symbol, even with slight change, and with the intention to act as the ISO symbol (eg international recognition) and for commercial use is copyright infringement. The reproduction would be "substantially similar."
ISO grants purchasers of the graphical symbols use "for the implementation of their respective ISO standard(s)" meaning in your literature, on the device, etc. - commercial use not including reselling the graphic file.