I know that is definitely not Grandma's Yellow. Princess Alice has tell-tale characteristics in the way it forms sprays, and the odd density in the way it forms its leaflets. The only things the two have in common are: dark gold color, repeat bloom and top-heaviness :)

Ive tried to ID Grandmas Yellow, but I can't. I cant even decide which yellow line(s) it is derived from! Ive thought of so many possibilities ranging from one of McGredy's lesser known yellows, one of the Hill yellows derived from Golden Wave, an old J/P yellow, one of the random Kordes yellows derived from Buccaneer or maybe a sport of a known rose. For example, a lot of older apricot/copper tones have a lot of yellow sports. There are just too many possibilities to even narrow it down. And the narrow yet rugged foliage doesn't help ID anything either. However, the most narrow yellow that comes to mind is New Day, so a hybrid of that is possible too =/