The potency you are describing, is built up mainly by the calyx of the cannabis plant. This is where the majority of the plants resin/most mature trichome heads will be located.
Each individual calyx has a pistil, as
@Quetzalcoatl describes. As the calyx matures, the pistil will go from a more vibrant, almost spiky white color, to a softer texture that begins to turn orange. When the calyx is mature, the pistil will likely have darkened further to a red color and might even fall off or recede back into the calyx at peak maturity.
There is no reason why a particularly hairy bud would be less potent. What you are likely noticing however, is a bud that was harvested a touch pre-maturely, as these tend to hold onto their pistils a lot more tenaciously, and so are that much more visible when it comes to bag appeal. This is by no means universal of course. Some strains like to hang onto their pistils and are still quite awesome. Blowfish, Blue Dream and Cherry Slider are some good genetics which tend to do this imo.
Overall, what you are looking for is calyx 2 leaf ratio in a bud, how dense are the calyxes, and how trichome covered. That is generally what will dictate potency in my experience. After that, it comes down to the tactile experience. How does it smell when you open the jar? How does it taste? Was it smooth or harsh? Is the high racy, and in your head, or is it melting and in the depths of your body? There are so many shades of quality to choose from, and the number of pistils in your bag is not what you wanna go by.