Care must be taken when correctly identifying lamps by Edward Miller and Company, USA. Many lamps are mis-represented, being identified as a lamp made by Miller from a Miller filler cap, flame spreader etc that has been placed on any old stray central draught lamp. This is also the case for removeable founts. Just because a lamp happens to have a Miller fount, again does not mean that the lamp is itself a Miller lamp. (Just because you might put the bonnet badge of a Porsche on a Ford - does not make the car a Porsche.)
Even more caution must be displayed when identifying flat wick lamps. The Miller company made eagle (flat wick burners) in the three main sizes (#0 #1 and #2) by the truckload and sold them wholesale to any number of glass manufacturers and other lamp makers. Just because a lamp that has a flat wick burner, with a wick wheel with the Edward Miller (E Miller or EM and co.) trade markes DOES NOT MEAN that that lamp is a Miller lamp.
There are numerous features, patterns and production types that idenfify a lamp to be that made by Edward Miller and company known to the expert. Unfortunately they are to extensive to list here, and requires many hours of studying the patterns used by Edward Miller to become competent in such identification.
Things become further confused by the actions of all major lamp companies who were happy to seller their components wholesale. Major retailers would source various parts for lamps from any number of manufacturers and 'built their own' so to spreak, creating in todays terms a genuine victorian hybrid lamp. Unfortunately today it is extremely difficult to distingusih these hyprids from modern day lamp repairs or restorers who 'marry' any old bits to complete a lamp and call it original.
If considering buying a Miller Lamp, and are unsure if the seller has identified the lamp correctly seek advise from a expert in the field.
There exists an excellent reference site for lamps made by Edward Miller. Its URL is the w's dot edward miller kerosene oil lamps (all one word) dot com