Navajo Old Pawn.925 Turquoise MOP Signed IP Ring

Navajo Old Pawn .925 Turquoise Mother of Pearl Signed I P with an = (equal) mark This could be an early Irene Platero ring with the =mark being the shop mark, however, I am not 100% certain. It is not marked .925 but it was tested and the results are pictured in the last two pictures. The red strike is positive for .925 Size is 7 1/2 MOP shows signs of wear and is not a brilliant as it originally was. Otherwise, the ring is in great vintage shape