A Heritage Roses member who volunteers re the Rookwood roses tells me that this one is seed-fertile.

I was blown away by the similarity of “Isabel Smith” to ‘Comtesse de Labarthe’ this morning. Isabel’s bloom was slightly darker on the reverse. But foliage looks identical.
I feel that it was quite likely that Bernede may have used his 1857 ‘Comtesse de Labarthe’ in the parentage for his 1859 ‘Mme de Tartas’,

Because both roses are said to have a deeper reverse, I compared
”Isabel Smith” (extremely narrow stipules) and
”Almerta Orchard Pink” stipules are wider and are glandular pedicellate.