I've never been able to find lumen ratings on the Mag-Lites... They were good lights, years ago, but Streamlights would blow them away as a duty light... Today they seem to be way behind Surefire or any of the other new led lights...
Maglight is made in the USA although some components are made in Canada and elsewhere.
Attached is link to the specifications for a 12" 3-D Cell LED.
Spare Parts > Anatomy > Mag Instrument, Inc. - Manufacturer of the Maglite® Flashlight
Mag-Lite measures light by Peak Candle Power (foot candles) rather than by lumens.
What is the difference? Well, without going into a lighting lecture I will try to explain.
The rate at which light is emitted by a light source is analogous to the rate of water sprayed out from a garden hose. The power or rate a which light is emitted from a lamp is measured in lumen's. For all practical purposes , the amount of of light emitted by lamps is given by the lumen value.
Lumen's however do not tell you how the light is distributed. You can have two equal reflector lamps that give off equal amounts of light (lumen's) but with very different light distribution patterns. The spot lamp and the flood lamp are good examples of this. The spot lamp has a very narrow beam while the flood lamp has a much wider beam with much less intensity.
Candlepower (or candelas) describes the intensity of the beam in any direction. The lumen's from a light source will eventually illuminate a surface.
The only accurate way to compare different types is to compare the light falling on equal surface areas. Illumination is the amount of light falling on each square foot of a surface.
The unit of illumination is the footcandle. If the light of 2,000 lumen's is falling uniformly on a table of 4 square feet, then the illumination of that table is 2,000 lumen's per square foot or 500 Footcandles. We do not want to see illumination but rather the light reflected from surfaces. A dimly illuminated white surface is much brighter than a highly illuminated black surface. The brightness of what we see is actually a function of both illumination and the reflectance of the surface. Since Brightness is the illumination reflected off a surface, it is also a measure of the lumens per square foot.
There is much more to this subject however this should give you a quick overview of how to convert Lumens to Footcandles. Peak footcandles only refers to a lamp at its peak. Most charts factor in a maintenance factor to slightly lower the results for lamps. LED's degrade very little.
The 12" 3-D Cell LED has an output of 22,000 Peak Beam power.