That is a great find. The paint looks to be in excellent condition! I actually do not have a 1201 with the headlight. I have a roof mounted headlight on a 1211 boxcab, but not on the 1201.
Here are some additional variations of the 1201.
The hardest variation to find is the one that uses decal lettering instead of rubberstamped letters. This appears to be the earliest of the 1201 engines and the best guess is that Flyer decided it was either too expensive to use decals or was easier to rubberstamp the engines. I have only seen a couple of these decaled engines (including a 1218 that was factory overpainted, over the decals)
Here is another early 1201. You can tell the early engines by the style and number of power pickups on the motor and the style of the wheels. The earliest motors had a single power pick up mounted on a long brass tab. The next power pick up (like the one on this motor) is a single pick up mounted on a stronger steel arm that is mounted more to the center of the motor. I mentioned the wheels are different, and you can see that the wheels on this motor have 8 spokes and do not have the steel tire around the flange. Flyer used this style wheel into early 1922, prior to switching to the 10-spoke wheels with the steel tire. I state this due to observed variations of the earliest 3020 engines.
The next variation is also an unusual one. Not sure why, but this engine never had handrails installed. This is evidenced by the mounting holes for the handrails being filled with paint. It also never recieved a pantograph.
This example also features an unusual motor variation that was very short-lived (I believe 1922 only, but do not recall the year). It features brushes that are contained wholly inside of the frame and a separate cylinder from the armature that the brushes make contact with.
Lastly, you mention the green variation for the 1201. I do not have one. I have both a 1218 and a 1217 in the following dark green color. I suspect that the green variation of the 1201 would be this dark green color.
I realize the above photo makes the engine look more of a black color, but in reality it is a very dark green color.