I would think it depends on the amount of choke. I ground/lapped in about .008" in a .44" smoothbore and it effected round ball shooting not at all. My current 20 bore has an improved cylinder, normal USA shaped choke and it shoots round balls quite well - 4 out of 5 into an inch at 28 yards. One of the 5 will open it to about 2" - me or the gun - who knows?
I will hazzard an opinion that a slight ,.005" to .010" jug choke, will not hurt round ball accuracy, but it will help very much with patterns. i don't think this choke should start more than 1" behind the muzzle, though. the 'end choke', or cylindrical straight bore diameter section at the muzzle should not be much longer than a typical shot load - ie: 3/4" to 1' is plenty long enough. Any longer than that and it may negate the tightening effects of the jug choke on shot.