My mother died in 2008. She had a will, but it hasn't been probated. Do I have to probate her will?

My mother died in January 2008. I was her Durable Power of Attorney. She had no assets other than furniture and personal belongings. Debts are settled. Funeral is paid. My mother has oil and mineral rights for which I am receiving checks every few months--but I haven't file a Change of Ownership to have her royalties transferred to my brother and me. My brother (age 46) and I (age 42) are her heirs. Do I have to probate her will? Is it a legal requirement to do so? My mother resided in Oklahoma at her death. I live in Texas. - Is this your question? Add additional information