@gurugeorge said
"Isn't there a specific place in Crowley's system where an investigation of the Qliphoth is recommended: Liber Carcerorum?"
That work itself is part of the 3=8 curriculum. However, there are no assignments regarding it and no tests required, other than the general 3=8 instruction to complete one's Qabalistic knowledge.
The final exam of the 1=10, after other astral tests have been passed, has always been to investigate the Q'lippoth of one's own Sun-sign.