Five of the 30 rare violins sold by Herbert Axelrod last year to the New Jersey Symphony might not be what he purported them to be, suggests an investigation. “They are old instruments, certainly, dating at least to the 19th century. But, the experts say, it is likely they were crafted by someone other than the famed violin-makers to whom they are attributed. In short, the experts say, they are probably fakes, worth a fraction of their appraised value.”