Hello. Find a Grave is a free database. You can look this up yourself, but what I found for the one born in 1913 is that he was born May 21, 1913 and died May 26, 1998. There is a picture of the marker and it appears that he was probably married to a woman named Alene. She was born in 1917 but there is no death date listed. This is from the Spavinaw-Strang Cemetery in Mayes County, Oklahoma. This doesn't mean that he (or the other Hugh Horton) were the only ones in Oklahoma. Also, it could be that your Hugh may have gone elsewhere. I hope you find the man you are looking for.
BTW. The Velma Horton that I found in Wheatridge, CO was apparently married to an Earl Horton, so she isn't your person either. I requested a picture of the marker and was lucky enough that someone went out today and took the picture.
Good luck in the search.