Love this discussion— food for thought about the construction… IIRC, Ewan McGregor tells the story of picking his lightsaber. That they came to him with a pelican case with several lightsabers and one empty slot (assuming Neeson got to pick first).
It’s very possible, borderline likely, that the initial props were developed off the concept art with a little more time and care, which explains why they were more scratch built than total founds part jobs.
As to The solid core vs rod theory— it’s possible that these initial props, likely heroes, were more precisely made, and once the actors made their pics, all the back up heroes, stunts, and whatever other versions they cooked up were made for their specific need— be they lighter weight belt hangers, stunts, close up heroes, throwable, etc. I wouldn’t be surprised if both methods were used.