Wow, nice find. One of these went for less than $25 in January; seller may not have known what he/she had. https://www.ebay.com/itm/372902887252 Devon
Not worth the trouble if you are going to pile up the miles. I ran one back in the late 70's(when you could just buy them over the counter) and piled up the miles. Two scorched areas were about to break through although not sure of the mileage. For the strip or less actual driving time should be fine otherwise block off the hole with plugs.