They are own root. Vendors will post this information somewhere on their site. Heirloom has it on their "Rose Information" page under "Own Root Roses". They will be smaller than bareroots, but for the more vigorous varieties, they will catch up quickly.

I'll leave it to someone in your zone to add more info.

Here is a link that might be useful: Heirloom Roses Rose Information

Aggierose, you may also find that many of the older Hybrid Tea Roses -- which were bred to be grown on rootstock -- are less vigorous on their own roots.

Jeri