It would be interesting to raise the issue with them, and i would happily provide notes etc to argue the point but sables would not be required surely? marten sables are a seperate breed from sables in the same way as are black tans and black foxes seperate from self blacks - both are derivative with the 'at' gene added.
I wasnt aware that New/Emerging classes had to be agreed before adding as there is no standard that is agreed? Sables have a 'provisional status' which is supposed to guarantee them a seperate class in NCC and SCC starred shows (not a guarantee that is always observed mind you!) other than that they just get entered in the novelty section below the pets!

marten sables bred together produce more martens and occassionally dilutes (referred to as sables! LOL) and do not require the interjection of sables in the line once established, although the best sables in terms of shading are in fact dilutes!
I know Im nearly the only silly sod daft enough to pursue these as a breed but they are gorgeous, even if they arent to everybodys immense interest - I now have sable otters as well and would really like to get these out and shown more!