Bulk vs Jarred tobacco.

I have not bought any tins yet. All I have are jarred bulk tobacco.

1. Would you guess that most of these bulk tobaccos have tinned counterparts, or are they housemade?
2. If a bulk tobacco is called Devonshire, does that mean it would be one of a hundred different brands?

The jarred tobaccos that I have bought seem to have generic type names, but no brand names.

3. How do I know what I am getting?
I assume the answer to this is to ask the person you buy it from, but I am just checking how many different tobaccos are out there with the same name.