Bullseye is wonderful practice for my rifle shooting (HP and smallbore), I can't imagine it wouldn't be even more helpful to the much more closely-related-to-bullseye skill "speed" pistol shooting. If you can shoot well one handed at 50 yards at a 3" 10 ring, or 5 shots in 10 seconds at 25 yards at a 3" 10 ring, I would expect you could pretty easily adapt to just about any rifle/pistol skill.
The bullseye shooters that I've seen give High Power (position rifle shooting) pick it up much faster than most of the rifle guys like me pick up bullseye.