Here is how I see it.

Although all three of them were printed in 1925, the top card is the first one in the series. The three cards are numbered from top to bottom (the number is in the bottom right-hand corner of the card) 102668, 106179 and 106170-N. The first card was printed by Curt Otto Teich and distributed by the Union News Company. The Union News Company, like so many other News companies, was wholly owned by the American News Company. From New York City, they distributed postcards and other printed items through the newsstands in major hotels and railway stations. It is printed on good quality paper stock by Curt Teich’s company. This card must have been very popular. It is soon reprinted by Curt Teich’s company. This time it is numbered at the top (collectors now have a series to complete!!) and a new number is given to it in the bottom right-hand corner. This time, it is published by the Sanborn Souvenir Company in Denver. Curt Teich has changed the name of the printing process from “C. T. American Art” to “C. T. American Art Colored”. The bottom rendition of the card has the same number as the middle card with a dash N added. The “-N” is an indication that it is a reprinted version of the original 106179 card. The collector incentive number is still at the top.

However, on the back, all one can assume is that the Sanborn Souvenir Company was the only company that touched this card. They must have struck a deal with the Curt Teich Company to be able to publish and distribute the duplicate copies of the original picture for their use. Two things hint at the Curt Teich Company’s involvement. First, the numbers are the same except the –N that indicates a Curt Teich reprint and second, it is printed on the Linen Style of card that Curt Teich developed. The other two cards are on good stock smooth paper. There certainly was a lot of development in the postcard business regarding this particular view in 1925.