If the guardian has given the bond, if any, required in accordance with this title, any sale, pledge, mortgage, or exchange by him, whether pursuant to a decree or to a power under this title, shall pass the full title of the minor therein, free of any right of his spouse, unless otherwise specified. Persons dealing with the guardian shall have no obligation to see to the proper application of the cash or other assets given in exchange for the property of the minor. Any sale or exchange by a guardian pursuant to a decree under section 5155 (relating to order of court) shall have the effect of a judicial sale as to the discharge of liens, but the court may decree a sale or exchange freed and discharged from the lien of any mortgage otherwise preserved from discharge by existing law, if the holder of such mortgage shall consent by writing filed in the proceeding. No such sale, mortgage, exchange, or conveyance shall be prejudiced by the subsequent dismissal of the guardian, nor shall any such sale, mortgage, exchange, or conveyance by a testamentary guardian be prejudiced by the terms of any will or codicil thereafter probated, if the person dealing with the guardian did so in good faith.