This is not entirely uncommon. Try to make sure the professor teaching the subject is actually experienced in it somewhat. Ask the school when and how often the courses are added. It certainly wouldn't be the first time a program has listed a course in its calendar and then you find out it has not been offered in five years. The make up of a psychology department is fluid.
New profs come on, old ones leave.
They often leave courses listed in the calendar simply because its a pain to remove it and then go through all the procedures to add a new class. If you find the 'holy grail' of forensic courses and you've decided this is the school for you, at least put the effort in to make sure the classes are actually still being offered. A lot of schools are now offering 'forensic' focuses for their clinical studies. This is actually the recommended approach by many. The clinical background offers you more career safety and possibilities then the strict forensic psychology programs.