Is Seiko GMT a true GMT?

I've been eyeing the Seiko GMT watch for quite some time now, but before making the purchase, I've been wondering - is it truly a GMT watch? With the plethora of timepieces on the market claiming to offer GMT functionality, it's crucial to understand the intricacies and nuances that separate a genuine GMT from the rest. Does the Seiko GMT offer true independent hour hands for each timezone, or is it simply a world timer? I'd appreciate any insights or experiences from fellow enthusiasts who might have had a chance to explore this watch in depth. After all, investing in a quality timepiece is a significant decision, and I'd like to ensure I'm making the right choice.