Lost Men’s gold ring

Men’s gold cygnet ring, engraved with three initials (RWB) on the front and 3 initials inside (MPL). Was my husbands fathers ring and he died when my husband was 16, it’s the only thing he had left him and he’s worn it for 30years so it’s hugely sentimental. He was riding a motorbike from karalee to esk and we have no clue when he may have lost it.