These brass kit cars were available in either 4-window "wide monitor" or 5-window "narrow monitor" variants. They included detail parts (from Miniatures by Eric) as well as decals. Got a picture of an assembled one? Do please send it to me!
Cars orginally assigned to the 104000 series were built over a span of decades, and at different locations. Purpose-built cars in this series were 42' over the pulling faces, and about 34' over the body. Others were rebuilds from pre-1880 passenger cars, and differed in length and window configuration. This is one case where a class of cars actually got less diverse over time - by 1940, the survivors had steel underframes, and two basic styles of cupola, and two body plans predominated: Some had been rebuilt with a wide cupola, others retained the unique long narrow cupola that looks like it came off a yacht (5 windows in pre-1902 cars, 4 windows in newer cars). The original body style had five windows on the side, the wide cupola rebuilds had four.
All these cars ended their service lives in the black/boxcar red/caboose red scheme. The last two five-window narrow cupola cars (one built in 1893) were retired in January 1961 and the last two four-window cars (one with narrow cupola, one with wide) were retired in 1964.