I knew the boxes were not from this model, but it's what it came in when I got it. Evidently the original owner had upgraded to a newer model, but somehow I ended up with the newer boxes and older machine. They still store everything nicely, though.
According to my research, and a few other collectors, the 516s did use this style bag near the end of production of that model. I have a nice 560 on the way as we speak, so I may swap it to that machine once I find a nice example of the "correct" 516 bag.
I did polish it all by hand using Mothers. A buffing wheel would probably be faster, but like all of my antiques, I like to "rejuvinate" not "restore". Polishing by hand is slower, but I think the finished product looks more natural. After all, these things are 60-70 years old now (and still out-perform the plastic junk you can buy today!)
With all of these Kirbys along with my toasters, coffee percolators, and classic cars, I buy mothers by the 5 gallon bucket!