The very first 550 baggage had four wheels, no door, wood litho and the type I or "winged" frames. The one above is red and the one below is the somewhat rarer white. Only the baggage came in white. There is a very unusual 8 wheel car that appears to have been made years later that used this same white body.

Underside of white car with close-up of winged frame.

Circa 1915-16, this car has the older wood litho but the newer rivet and spring frame. 

Circa 1915-1916 - This 551 has the early litho with the later frame.

Circa 1916-1918 - Later litho with early frame - car below has green roof.

Circa 1913-1915 - Early car with early wood litho on early embossed wing frame. Note that this car is a lighter red than the car below

Circa 1915-16  - Early wood litho with later frame.

As usual Ives used up everything, here's a Harvard body on an early 550 series frame. Below is the same body on a later 550 frame.

Yellow variation of the No. 552 using the Harvard body.