Was there a convertible Lincoln Mark 5 available by any after market coach builders in 1977?

There's no record of any reputable aftermarket coach builder offering a convertible conversion of the 1977 Lincoln Mark V. While some coach builders converted other cars into convertibles, the Mark V's substantial size, weight, and complex roof structure would have made such a conversion incredibly difficult and expensive, likely making it commercially unviable. The structural integrity of the car would have been significantly compromised without extensive reinforcement.