I think it was probably a factory racer as it has the 4-wheel disc brake option.
Indeed! I'm sure I've seen photos and documentation showing Donald Healey and Carroll Shelby racing this rare example in the 1959 Sebring 12-second race.
My contacts at Bonhams would like to talk to you about consignment.
Please do not wash or otherwise remove any dirt, dust, cobwebs, etc. and it greatly diminishes the value to the purist collector.
And if the original quick-lift jack remains with the car, I'd say you're looking at "comfortable retirement money" there.
By the way, I have an appropriate
Owner's Handbook for it, signed by Healey himself. POA.