There might be some doubt out there because of damage due to misuse or lack of care, but for those of us who have fished them for years and take care of our gear, there is nothing unproven about AGS guides.
The warranty is 5 years against defects in materials or craftsmanship to the original owner of the rod with verified proof of purchase new from an authorized retailer. Megabass does this (3 years pro-rated after year one), and I understand some other brands have gone to a 1 year warranty, or a serial number verification process for their warranty.
I'm glad to see the shift away from "lifetime" warranties on fishing rods across the board. It causes too many problems and unreal expectations. We're talking about a fishing rod here, not a hammer