First Mallets for 3' gauge?

American Locomotive Company built two Mallets articulated compound locomotives for the Colombia National Ry, in May 1909. These were ALCO #46168 and #46169 and built with a wheel arrangement of 0-6-6-0t as they had side hanging water tanks but not a saddle tank. Using 13&20.5x20 cylinders they could run compound 23,400 TE or simple at 28,100 TE, same as the later K-28.
Were these the first 3' Mallets built in the US and were they close in design to the same year 0-6-6-0 of DNW&P that were SG? I see ALCO built a South African 2-6-6-0 (NG-1062mm) two months later. For YukonMike: they had wheel back-to-back 32 3/4" and extream width of frame was 30.5" (Inside frame). Cyl. center line was 63" apart so there was 11.25" from wheel to center of rods each side (5" tire).
Great construction plans and photos of this engine were in a article in the Ry Age Gazette 2/18/1910. Was this AlCO's first Mallett?
Does anyone have the scrap dates of these engines, originally #20 and #21?