Only if there are actual inclusion bodies present in the liver. Remember, while the presence of inclusions is a diagnostic for the disease, the absence of these inclusion bodies does not necessarily indicate that the snake is not diseased or is free from IBD.
They could be in the:
............gall bladder
............brain
............esophageal tonsils
etc.
My female went through a liver and a gall bladder biopsy (ultrasound assisted). No inclusion bodies.
The inclusion bodies were found in her esophogeal tonsils........
As for the rate of incidence - I believe it's south of 70% but higher than your local boa breeder would leave you to believe.
Don't take my word for it - Dr. Jacobson has proven himself reachable by e-mail - even to members on this forum.
Instead of asking specifics from a vet who only sees a couple of confirmed cases a year, or worse a breeder who will most likely deny IBD is even a problem, e-mail the man who's spearheading the research and see what he has to say.