No, it isn’t, the Schweser notes are absolutely sufficient. I only used the Schweser notes, and I studied for a month on them and aside from ethics, there was only 1 question on the test that I hadn’t seen the subject matter for, and I’m pretty sure it pertained to a part of the Schwesers that I never bothered to read.
The comments on here that you’ll miss specifics covered in the regular CFA materials I completely disagree with (apart from ethics). I think that line of thought stems from a sense that you should be explicitly provided with the answers to the questions they ask. That isnt’ the point of the course of the prep materials.