When an agent finds a manuscript gem, can they make an offer independently? Meaning, do they need the agency's okay first? What about junior agents, or an assistant just breaking into the business and dipping her toe into agenting?What are you worried about here?
There is no industry standard, and any agency practice is specific to the agency itself.
So, the answer is: it depends.
Obviously someone very junior will most likely need advice.
Whether s/he is required to get permission is something you can't know, and an agent most likely wouldn't tell you.
If a prospective client asked me that, I'd be mortally offended, so be careful here.