Hank,
I found them easily online. There is a website I found called www.rockauto.com , They stock both sides lug nuts. They show a Wagner part # for the STD thread ones at BD61281 and the reverse thread ones at part #BD61280, They are only between 80 and 90 cents a piece there. Also NAPA auto parts may carry them locally for you. Hope this helps You could also swap out the reverse side studs for regular studs and STD lugnuts so you do not have to go through this again. As far as the tailight picture goes, most 58 plymouths had these tailights. Good luck with the project. One of my favorite cars. Don Jr.140CAO7SES8.jpgplymouth_plaza_54-58.jpg