I am not 100% sure about this, but I seem to remember that I have heard that as long as you give credit to the TCR guide for the numbers, then you (or anybody) are free to use the numbers for any reason you like. That is why they designed the numbered system, and I beleive they (the TCR authors) encourage collectors to use it. They (the authors) want their numbers to be the standard reference in the hobby.
I hope this helps, and remember like I said, I am not 100% sure. (I would say I am 75% sure)
Is there anybody out there who can help me out with this? Am I right?