[@Penultimate_Pi]
The rules for obtaining additional weapon systems does apply; Lorenzo's vagueness in his words and his meaning of compatibility can be interpreted as the effect on the synchronization rate or how compatible the weapon is with the pilot's level of expertise, which would be a negative in Lora's case. Of course, there is also the option that the sword replaces one of the Blaster Cannons and later added as a new weapon system.