I have seen many Kirbys from the 516 up to the Sanitronic VII be re-trimmed in the same tan hue the VII used along with the 562 and DS50, so on some of the older pre-562 machines -- especially when rebuilt by local mom-'n'-pop vac shops in an entirely different color such as green (Dual Sanitronic 80), brown (Classic 1-CR), rosewood brown (Classic Omega 1-CB), red (Classic III 2-CB) or blue (Tradition 3-CB) -- it is hard to tell what the actual model number is unless you look at the model plate on the bottom, which is often either removed or had its model number scratched over whenever rebuilt by some of these local mom-'n-pop vac shops.
Many years ago, I used to see a Kirby of this vintage re-trimmed in blue: it had the DS50's light cap with the light-up bezel on the top, but it also had a 562 or VII belt lifter, and a Tradition 3-CB handle assembly; so the actual model number per the main unit remains a mystery.
Your Kirby 519 was built in 1959, originally with mostly red trim but a gray bag with the Kirby logo on the front, with the Em-Tor bottom and wheels being gray.
~Ben