Cut nail like used for concrete, I would take a torch heat the nail red, let cool cut to the length you need and use a bit of epoxy in the hole and very carefully TAP it in. The heads on these look very similar to hand made nails, the heating will take some of the brittleness out of the nail and the cut to length will ensure it is not too long for the existing hole, use a broom straw to measure the hole depth. and carefully TAP it in, will lessen the chance of stock damage such as a crack or split, If the nail is too wide do a bit of filing for fit. the epoxy is just a added security hold. Or make one 1/8/th round stock can be bought at just about any hardware store, a hand held torch and some pounding instant nail. why buy and wait for ever on a nail if you can even find a nail of this type.