By the information you have given it is very difficult to ascertain definitely whether she is taking percoset or not. Usually percoset or oxycodon is a drug of opioid
group and it has been used in cough
formulations and in pain medications.
Usual strengths prescribed by doctors are not orange colored but if you want to clearly assured then you have to investigate more.
Other option is to talk with her directly as she is your child and you can talk with her, talking always help.
It is possible that she can easily clarify your doubt.
thanks, hope I tried to clear your doubt.