Congrats
I've worked with a lot of rehomed/rescued gliders, it's very common to not get any history on them.
"He/She is completely unsocialized, skittish, etc..." She may have been social with her former owners. The fact that she isn't social and calm with you is because you are new to her, the environment is new to her, possibly the cage is new to her, what your feeding may be new to her everything she previously knew is different.
It isn't out of the ordinary for a glider to be different with a different human.
Example, A friend of mine gave me one of her gliders, she gave me the complete background on him, he wasn't getting along with her 2 females and he'd need some work, he never went up high and never glided. We brought him home, that day he was ontop of my head, gliding, climbing up high and gliding to me... totally different glider than my friend knew at her house. I took videos and pics to show her and she couldn't believe it was him.
I've gotten a 12 week old joey from my best friend who was such a sweetheart at her house, he'd cuddle up and go to sleep in her hand.... he was very socialized and held by everyone in the house. When he got to me he was a demon child. It took almost a year and a new cage mate before he became sweet and social with me.
I can reach in any cage of mine and get gliders out and handle them with no issues, but no other person I know could come into my house n do the same thing. My gliders are socialized with me and my boyfriend but no one else. I've had 3 joeys born here that are the mossssssssst sweetest babies on earth and I feel they are very socialized......right up until I hand them to someone else and the gliders realize it's not me holding them. Thats the only time these babies crab the first time it happened I was shocked as I never heard them crab before lol
Anyway my point is gliders behavior can and do change and thats at any age, she just needs to get to know you and vice versa.
Crabbing, barking, even sleeping/not coming out of the pouch is normal for new arrivals. Be patient and don't be to hard on yourself
If you don't have one yet get a bonding bag and start doing bonding bag time with her if your not sure what that is we can explain it.
also tent time, is great for letting them explore you on their own terms while keeping them contained rather than chasing them all over. Sometimes thats unavoidable I had one of my newer boys leap out of the pouch onto me then off and running on my bed today... it happens lol just try to collect them calmly