Hi Michael,
The glazing of the cabin on the MiG-1 was changed during the production process. On the late MiG-1, the glazing of the cabin was like that of the MiG-3.
MiG-1
http://www.airpages.ru/draw/i200mod.gif
http://www.airwar.ru/image/idop/fww2/mig1/mig1-1.gif
http://www.airwar.ru/image/idop/fww2/mig1/mig1-2.gif
MiG-3
http://www.airwar.ru/image/idop/fww2/mig3/mig3-1.gif
http://www.airwar.ru/image/idop/fww2/mig3/mig3-2.gif
The main difference is the fuel tank under the pilot seat.
Displacement of the engine can be seen from the nozzles in the top view. The wheels were 600 * 180 (MiG-1), and was 650 * 200 (MiG-3)
Cheers,
Kirill