I hope someone more familiar with swords can give a fuller answer, but one area we can see personalization are in the short inscriptions on the lead bullets hurled from slings, which in my personal opinions makes up one of the more entertaining sources of information in archaeology. These ranged anywhere from saying "for victory" to "Lucius Antonius, show your ass". One of my favorites just says "catch!"

Before the Marian Reforms, soldiers were not equipped by the state, so all weapons and equipment were privately owned. While there were regulations and requirements for what each kind of soldier would be required to bring, all weapons and armour were personal to a greater or lesser extent.