possibly Chancery court petitions, 1806-1851 but they are requests by parties seeking redress - I think someone would have to petn to make the boy a ward of court for the court to appoint a guardian - it was possible for those over 14 to petition for a change of guardian/overseer if they found any relationship with the court appt guardian uncomfortable (sometimes you see a request to switch to a different uncle etc mentioned in annexed documents to a will(in which it was possible for the parent to name a requested overseer) or an intestacy decree) but suspect these petitions went thru the consistory(church) court system