My personal favorite spelling is Djogyakarta.
Anytime a language is translated outside of it's original alphabet these spelling variation are bound to happen as the English aphabet struggles to find the right letters for the proper sounds. Ys and Js are often interchangable in many language translations.
Numerology is very common in Java. The number 319 might hold a very personal significance to the original owner, one that we will probably never decipher.
I have found this Djogya hilt form to be generally smaller than it's Solo counterpart, so i don't believe this is due to it being made for a smaller hand size, just the style.