Are there any skills that actually cannot be gained via the Press-Ganged origin path?

Question

The Press-Ganged origin path in the Core Rulebook reads (emphasis mine):

Thanks to your shadowed past, you have picked up some knowledge along the way that you would not normally have access to. You gain a single Skill (so long as it has no prerequisites) for your character.

So far as I can tell, there are no skills with prerequisites. Even skills that seem like they honestly ought to have prerequisites do not. The specific case that interests me the most is Psyniscience, which is not ordinarily available to any non-psychic Career Path and which seems like it should be only available to psykers, yet does not mention any prerequisite of having a Psy Rating. Nor does it explicitly state that it requires psychic ability to use the skill.

1. In the general case: Are there any official or semi-official rulings in errata, FAQs, or words from the developers that clarify what skills can be acquired via the Press-Ganged background?
2. If the general case is not answerable, are there any official or semi-official rulings that clarify whether Psyniscience in particular can be acquired by someone without a Psy Rating?

Please support your answers with citations, if possible. I'll accept supplementary information written for one of FFG's sister games (Dark Heresy, Black Crusade, etc) if there's no Rogue Trader ruling.

Answer 1

I brought this question to Fantasy Flight Games themselves. Their official reply to me is as follows:

"Hi David,

Good question!

He can take training in any one Skill except Psyniscience, which requires one to be a Psyker. No other Skill has a Prerequisite, so all other Skills are eligible choices.

I hope that this helps!

Max Brooke, RPG Producer, Fantasy Flight Games"

I believe this answers your question accordingly.