I guess you could say that COR is their job boost, and since you'll always have a COR in the party using them you would never NOT have the job boost.
OK if no job boost, then does AF2 hat have any effect?
And is there actually a speed boost with different rolls on bolters?
1) AF2 hat doesn't have any effect on Corsair's Roll, so there is precedent in AF2 hat doing nothing for a particular roll. If we're assuming that COR is the associated job to the new rolls (I think this is probably a safe assumption), the Tricorne shouldn't have any affect.
2) Keep in mind I haven't personally tested either roll, but from people who are playing around with it they claim there are different speeds with different rolls on Bolter's. Bolter's is likely harder to test to get true numbers, but you could probably get a close enough baseline to at least tell worse/same/better than other players with either:
a) A different number Bolter's Roll
b) The 5 different levels of Quickening from the Swift Shoes super Kupower
c) Various movement speed gear (many 12% pieces, 8% ASA legs, 25% NIN AF feet)
d) Other movement buffs (Mazurkas, Spectral Jig)
The best thing about Bolter's is that it does seem from reports to stack with movement speed gear (including Quickening).
Are those numbers confirmed? Unlucky roll on everything else has been 4 over the lucky number. Not saying it hasn't happened, but it seems odd for SE to change the formula.
Again, I can't personally confirm anything. But the numbers on Wiki seem too specific to be just pulled from out of nowhere. It does seem odd, and that's what prompted me to make the topic to begin with. But doesn't seem completely unrealistic to think that SE would deviate from the standard with these new rolls, which are already a bit odd in that they don't neatly map to the 20 jobs.