No, they are not identical. The "all in one" is a bound copy of the sixty mail order lessons from 1928.
The Tarbell Course
books were published in 7 volumes starting in 1941. The first five covered the original 1928 course, reformatted and edited into categories for book form. Vol 7 came many years later (1972) and was compiled by Harry Lorayne. You'll even find a submission in there from a young David Copperfield. Vol 8 was described as a "Graduate Course" and was published in 1993.
As a collector, the original mail order set is an interesting addition to any library. But, the 8 volume set of books is far larger and covers more material than the original course.
Go with the 8 volume set.
http://geniimagazine.com/magicpedia/Tar ... e_in_Magic