Regarding rebuilding light bulbs....there was an early form of construction known as the "stopper" type in which the filament was contained in a sort of bottle stopper which was inserted in the base of the globe.....obviously this was a simple matter of removing and replacing, along with evacuation of course. Perhaps this was the flavor of bulb that Sylvania rebuilt. Way back when, labor was cheaper than parts so this may have made economic sense at the time.

Anthony