I agree with clark it is not Gnostic, by definition. But, with that said, it definitely fits with more ancient esoteric religions and groups out of which Gnosticism was created.
I do have to differ somewhat, though. The Book of Enoch was created over a 300 year time period, 100BC to 300.AD. So, while not Gnostic, it does contain some Gnosticism.
Such as the quote from Jude, above, was written after Jude wrote his book.
All things should be read and studied prayerfully, I fully agree. Understanding the Enemy helps in defeating him.
This might help.