Thumb notches are standard on quite a few knives Tom. If, by full tang, you mean a full exposed tang it's not an option and the wrist thong is included on exposed tang model, i.e. #14,#15,#16,#17,Fireman, CC/FT, #28, etc. Thumb nocthes are also standard on the #16 and Fireman as well as the #28...
Capt. Chris