If you open both the Gradient and Swatches panels you can click on the individula stops in the gradient and if they were created from swatches the correct swatch should highlight, If you don't see a highlighted swatch, you can get the color formula for the stop from the Color panel instead.
But that doesn't guarantee that the gradient stops have anything to do with the solid color you want to apply to your type. You can use any colors you like in a gradient, and any solid color you like for the text. Keep in mind that if you are using anything but 100% k or a spot color for the type you run the risk that it will be fuzzy, especially in small sizes and especially if the color is fairly light. Process colors are mixes of dots and won't have the same crisp outlines as type made from 100% of a single color.