(a) If all subscribing witnesses have died or have left the State or have become of unsound mind or otherwise incompetent or unavailable, the execution of such instrument, except as provided by G.S. 47-12.2, may be proved for registration, before any official authorized by law to take proof of such an instrument, by a statement under oath that the affiant knows the handwriting of the maker and that the purported signature of the maker is in the handwriting of the maker, or by a statement under oath that the affiant knows the handwriting of a particular subscribing witness and that the purported signature of such subscribing witness is in the handwriting of such subscribing witness.
(b) Nothing in this section in anywise affects any of the requirements set out in G.S. 52-10 or 52-10.1. (1899, c. 235, s. 12; Rev., s. 997; C.S., s. 3303; 1935, c. 168; 1937, c. 7; 1945, c. 73, s. 11; 1947, c. 991, s. 1; 1949, c. 815, ss. 1, 2; 1951, c. 379, s. 1; 1977, c. 375, s. 12.)