I've just spent half an hour searching for an answer but the only name I can find for him is Jay R. Smith. I suppose the only way to find out what the R. stood for would be to obtain either a copy of his birth certificate or of his death certificate.
Be aware that I am autistic, so my mind does not work in the same way as the minds of the majority of other people. I have a tendency to do things differently and to react in unexpected ways to situations. I may come across as quirky and eccentric or just plain weird. I am very literal and prone to 'black and white' thinking.
As I recall, the "R" doesn't stand for anything. It was just something added to his first name. Whether this was part of his actual birth name, or just something added while he was a kid, I don't know.