Are the hides from H&M vat dyed? And exactly what does that mean?

When shopping for a sofa the furniture store told me that the H&M hides are "vat dyed" so the color is consistent throughout the leather. The leather samples I saw were this way - the same shade (or very close) on both sides. Is this the norm? Was the salesperson correct?

Thanks

Read through this thread and you'll know way more than that salesperson afterwards

http://www.myfurnitureforum.com/show...-FORUM-lt-READ