Kirbys are hard to kill...
You've got a good project on your hands and it's cool that it's a childhood vacuum. I think the Heritage/Legend series are my favorite Kirbys to work on. I went on a bender with those machines between last September and early March of this year. I refurbished a Legend II last fall and a Heritage 1HD this past spring. In between the two, I snagged a Heritage II Legend for $15 that was in absolutely pristine condition except its cord was missing. I guess somebody made an extension cord out of it.
Are you completely missing the bag assembly or did you just take it off because it was damaged? For what it's worth, the Legend II is completely identical to the Heritage II except for the color and for many parts the red Legend II replacements are not readily available. I had to replace the foot switch on mine with a black one for a Heritage II. It looks fine, though. If you're not picky about the color, Heritage II bags are more readily available and tend to go a bit cheaper than Legend II bags and a gray Heritage II bag looks pretty good on a Legend II with the red bag topper and guard band substituted. For some perverse reason, I swapped the bags on my Heritage II and Legend II. Aesthetics and missing parts aside, how does it run? Keep us posted on your progress.