Well worth having. The historical booklets enclosed complete the experience. The original recording company can be discovered by checking the source of the copyright on a recording, or by seeing who the performers are, due to the long term relationship of performer, or orchestra, with a particular original label.
If the box is sealed, $1-2 per record, plus $2-3 extra for the mint NOS status would be fine for the box set. Of course, even cheaper is better, and you didn't mention what price you would be asked to pay by your seller.
Most recordings are enjoyable, but with such a series you are paying for musical enjoyment rather than audiophile excitement in every selection. The oppportunity to hear repertoire, and performers, and learn much about the composers, would be the main attraction. Among hundreds of selections there is variability due to original recording company.
The fun lies in becoming familiar with so many fine musical works, and past generations of worthy performers.
If the boxes are open, then check for cleanliness, and scratch-free status.
To start, check out a box in the named composer series, and another in the historical interval series to see if in this sampling there is the musical and audio quality you are hoping for.
