The picture on the left shows the wick raiser knob on the early production model-2 lamps. It was held in place with the use of a set screw that tightened down on the shaft of the wick raiser knob. The picture on the right shows the wick raiser knob on the later production model-2 lamps. The set screw was eliminated.
The photo on the left illustrates the protruding rolled threads of the early model-2 lamps. The threads you see are not part of the burner, but rather part of the oil font itself. They were made to accept the threads on the burner and allow it to screw down onto the font. The photo on the right shows the later production model-2 lamps with a design change that eliminated the exposed rolled threads on the font. Both lamps in these photos had already been redesigned to eliminate the set screw on their wick raiser knobs. While these two lamps look quite similar, you really need to look at the details of the early metal lamps to see how they may differ.
The above picture shows the variations in the foot of the model-2 lamp. The picture on the left shows the embossed foot design of the early lamps, while the picture on the right shows the plain foot design of the later lamps.
The 201 glass shade was a fancy opal white glass shade that was designed for early metal lamps. (models-1-4). It has been reproduced, but the original lamps will have a mold mark that runs from the top of the shade down to the lower "valley" in the design. If you look close you can see the mold mark in this picture.
