Thelemic magical practices are the same as the Golden Dawn's, plus a couple of extras. Those extras are mostly in there.
Early Thelema (such as from the Equinox and related material) are more akin to Golden Dawn, AC was in the Golden Dawn for some time and based his work on that.
Later works, such as Book 4 went their own way quite a bit. Still. I guess this isn't a place to debate the fine details of Thelema or whatever..
A lot of Thelemites think their religious practices are somehow also magical, which is as true as saying the Catholic Mass is magical, but no more than that. So you don't see much there about the Gnostic Mass if that's what you meant by practices (because, let's face it, the 'magical practice' of 90% of self-proclaimed thelemites is MAYBE doing the middle pillar or Resh or the LBRP, going to a gnostic mass if one is close by, and getting stoned while talking about kabbalah).
Like many occult groups, cults, religions etc, people bring a lot more to a particular practice than just that.
Thelema, Golden dawn or whatever gets more vague the closer you look at it and when you really want to "do" something, you need to bring a lot of your own knowledge, research, experience and creativity into it, that and whole whole thing is very personalised.
Are most people in any group (whether mysticism or anything really) just "Doing the motions" and there to socialse or just waffle on about whatever? yeah sure, but that's pretty much always the case wherever you go and whatever you're into.
Anyway, thanks for the clarification of the content in your RPG..
There's three components to Thelema:
1. The mystical revelation and Holy Books of Thelema. These do not play a big part in the Invisible College RPG, though Aleister Crowley (now one of the Secret Chiefs) is given an entry and reference is made to the Liber AL.
2. The magical system of Thelema; principally the A.'.A.'.
In the Invisible College RPG, the College's curriculum is essentially the curriculum of the A.'.A.'., in terms of the mastering of specific magical theories, practices and techniques at specific degrees.
Many of the particular rituals that Crowley wrote himself were either reimagining of existing rituals (the pentagram and hexagram rituals, the abra melin ritual) or of other cultural practices (bhakti and raja yoga, past life recollection techniques, etc). So in the magic system I don't go into too much detail about the texts of the rituals; for example, I talk about Banishing as a ritual, but that ritual could be the LBRP or the Star Ruby, as either ultimately work the same. Ditto for the cultural practices.
3. The religious and fraternal activities of Thelema: the Gnostic Mass, Ecclesia, and OTO. These are barely mentioned.
And as to the second part of your comment, you're quite right, and that's a part of what I talk about in my introduction to the game. I make it very clear that the world of the Invisible College is one just like ours, in that 90% of occultism is crap and 90% of the people engaging in occultism are either posers or frauds or just too undisciplined to do anything other than treat occultism as a 'community' or a 'lifestyle'. And (I hope) it's pretty evident in the text that it is not one specific 'denomination' or practice that is the one true way but that 90% of everything is garbage, and the other 10% is from people who push themselves to the limit and discover real Truth.