-Check with the large automobile auction houses like Barrett Jackson and Mecum. You know the ones that are on Speed channel that sell cars for ridiculous sums of money.

-As rscamaro suggested an original vehicle with that low mileage (if it is actual) would be best sold by a reputable vehicle auctioneer.

I think I would have it appraised by an antique auto appraisal service if there is one in your area. One thing to keep in mind is that the odometers on the older vehicles are fairly easy to turn back, so depending on how much you know, and can verify, about the vehicles history that is going to be one question in the minds of prospective buyers. A competent appraiser should pretty much be able to verify if the mileage is accurate.

-There is a national association of auto appraisers. I don't know what the qualifications to belong are, but someone who specializes in older stuff can help you with an accurate appraisal. Usually runs about $40. Hemming's also has a big section listing appraisers.