Circa 1925 - Earliest brass plate models, this one has type III frame, cast iron drivers but nickel rimmed die-cast pilot wheels. Compare it to the 1926 model below with type IV frame and all die cast wheels.

Circa 1926 - Type III frame with nickel rims on all wheels. Count the steps and the cotter pins and then compare with the earlier 3243s.

Circa 1926 - this one is red.

Only seen a couple of these, same gray as 3242. This one was originally red and factory repainted.

Circa 1926 - It's not clear if IVES made any brass plate white 3243s. The one above looks original, but since we've never seen any cars from this time period, we would have to assume it's not.

Circa 1927 - Very scarce dark green 3243.

Circa 1927 - Light green above and below, type IV high frame.

 Same color above and below but it would appear that the closer the engine gets to 1928 the more 'puke green' the color becomes.

Circa 1928 - maybe rarer than the black one that year - this pale green 3243 has brass window inserts. We believe this to be from early 1928 as it has no brass doors. We have only observed the brass door inserts on the black and cadet blue 3243s.

Circa 1928 - The 3243 above is cadet blue and would appear to be from early 1928 as it has the brass window inserts. The 3243R below is also cadet blue, but note that this one also has brass doors, a feature that is usually associated with 1929 or later. The 3243 was last cataloged in 1928. Late 3243 also have the Wide Motor

Circa 1928 - The black 3243 above has brass windows and a stamped steel frame (same frame as the 3245 short cab). This variation was shown in the 1928 catalog. We believe it was necessary to use the steel frame on the 3243 when it was used to pull American Flyer bodied cars. The black 3243R below has brass windows, brass doors and the old cast iron frame from previous years. This is believed to be the last 3243 made by IVES. Note the plate on the right reads 3242R, supposedly IVES ran out of 3243 plates and used these. All the black 3243Rs that we've seen had these 3242R plates on them. We've also seen this engine with NO brass doors and there is at least one with a Cardinal Red frame. 

There's an exception to every rule, although most black 3243s have at least one 3242 plate this one has two 3243R plates. Everything else about this engine is original so we have no reason to doubt the plates. We assume this to be early 1928 as it has the brass window frames and no brass doors.

Circa 1927-1928 - I have included this picture because the owners believe it is original - based on what I can see from the picture I would have to say it is not, but you decide. This black engine has no door inserts or window inserts it has two 3242R plates - the pantographs are not clipped and it has a two grove whistle.