I don't see how the manufacturers will have to change anything other than what they print on the cover. MAXIMUM of 375 is what they've been producing, I presume they try to get as close to 375 as possible without creating a bunch that will be rejected. 325 +/- 50 still has a maximum of 375. If manufacturers can hold a tolerance of +/-5 (hypothetical), they will shoot for 370.
I don't think the new balls will carry any less.
I don't think the new balls will carry any less.