If it's a legal ball, it's a legal ball. "Obviously different" doesn't make it illegal on its face, nor does heavily scuffed and used make it illegal if it's properly inflated.
Where I am, there's always a ball switch for the free kick and if there is a "kicking ball" that's the one we use. Generally, a try down uses the previous ball and the ball boy leaves the "kicking ball" under the goal post -- the BJ retrieves the kicking ball for the free kick while the ball boy shags the one used for the try.
As it's often said, "When in Rome....." but if a team tries to insert a "kicking ball" on ANY free kick,
that's the ONE (the official who checks the ball
PRIOR to handing it to the kicker) considers most carefully. If
HE doesn't like it, it's rejected, and another ball is provided by the kicking team (
for SIMILAR inspection and approval), and there's
NO SUBSEQUENT DISCUSSION.