Yes, the Z Grills 3-year warranty applies to grills purchased through authorized retail channels, including Amazon, as long as the grill is sold directly by Z Grills and not by a third-party reseller.
For Amazon purchases, you should confirm that the seller is "Z Grills" and not "Fulfilled by Amazon" or a third-party seller. If in doubt, feel free to reach out to customer support with your order details for confirmation.
If you have purchased from an authorized seller and have proof of purchase, your warranty should apply as expected.