You need to know the model of rolling block; the 7mm bears a 1909 patent date unless I am mistaken. Also relative to a comment by Dingus; I don't believe "not commercially available" was ever in the firearms act. I believe it may have been policy but not written law prior to 1995 and relative to the registration of antique handguns. I suspect it is also used by instructors of the firearms safety course, who are not particularly familiar with the written law. I am not sure if the subject of antique registration is actually examined for with the firearms safety course.
cheers mooncoon