Okla. Stat. tit. 58, § 58-82: Special requisites of proof

No will shall be proved as a lost or destroyed will, unless the

same is proved to have been in existence at the time of the death of

the testator or is shown to have been fraudulently destroyed in the

lifetime of the testator, nor unless its provisions are clearly and

distinctly proved by at least two credible witnesses. For purposes

of this section, a copy of the alleged lost or destroyed will can be

admitted into evidence, whether or not the copy reflects the

signature or signatures appearing on the original will, if the copy

is properly identified, and the court shall determine what probative

value, if any, is to be assigned to such copy.