Circa 1925 - No 20 missing drive rods but note overhead headlight, two-piece steam chest and straight piping across the boiler behind the boiler band.

Another example from Circa 1925. The locomotive below is actually stamped with the No.  17 but it's the same casting.

The No 20 was cataloged in one set in 1925 and for separate sale, it came with a reverse. Note the two piece steam chests, the headlight is on the top and there is an extra row of rivets when compared to the No 19 locomotives.