Oliver Nos. 2, 3, and 4 were distributed throughout Europe by a company called Fabrik Stolzenberg (Stolzenberg Factory). They were based in Oos Baden-Baden, a city in Baden-Württemberg in southwestern Germany, with subsidiaries in Berlin, Hamburg, and Cologne.
Fabrik Stolzenberg sold the Oliver No. 2 as the Oliver Monopol-Stolzenberg. This name initially carried over to the Oliver No. 3. Sometime between serial numbers 55756 and 89075, the "Monopol" was dropped and the Oliver 3 machines were branded as "Stolzenberg". Once the Oliver No. 4 was introduced 1904, Fabrik Stolzenberg sold it as the Oliver Stolzenberg No. 4.
Aside from the decals, the only major difference from the standard Olivers sold in the US is the margin release keys. US machines have black keys labelled "Right" and "Left"; these are the larger size keys used for the "CAP" and "FIG" keys. In contrast, machines sold by Fabrik Stolzenberg use unmarked white keys as margin release keys. These are the same size keys used for the characters on the keyboard. It is also worth mentioning that the Monopol-Stolzenberg No. 2 has a white left margin release key whereas No. 2s sold in the US didn't have any margin release keys. It appears that the left margin release key on the Oliver 2 is a feature that is only seen on machines sold in Europe.
The serial numbers for the Oliver Monopol-Stolzenberg and Stolzenberg models are intermixed with their respective serial number range. Therefore, it is hard to know how many of each model were distrubuted by Fabrik Stolzenberg. I have the only Monopol-Stolzenberg No. 2 known to exist. I know of three Monopol-Stolzenberg No. 3 machines in existance. The Oliver Stolzenberg No. 3 is by far the most common Stolzenberg model; there are so many that I have lost count. In contrast, I only know of two Oliver Stolzenberg No. 4 machines in existance.