I guess it might depend a little on how skittish squirrels are in your area and how you hunt them. As Skychief said, the cylinder bore is as versatile as it gets. On a large private piece of property I have access to, the squirrels almost act tame sometimes. Getting very close by slowly stalking is not an issue and my cylinder bore works perfectly well. I can shoot squirrels out to a maximum of 25 yards or so with a load of #6's and 50 grs of 2f.
But, if I head to areas that receive squirrel hunting pressure, those buggers are hard to get close to and wary as all get out. A full choke would be a bonus in that kind of area and last year I built a Kibler SMR in .36 instead of even using a smoothie with shot just for that reason.
So in making your decision, consider the squirrels you hunt as well as other ways you might want to use that gun with shot and that might help make a decision on if you want choke and if so, how much.