The original bayonet was the 'Model of 1905'. US nomenclature changed around WWII and several vesrions existed
The model of 1905 was 16" overall and had two styles of wood grips, ID'd by the number of machine marks
There was also the M1 bayonet, which seems to have been specifically for the M1 rifle, but don't let the name fool you. They were made for the 1903 rifles as well. It is simply a 10" vesrion of the Model of 1905. Grips are plastic, The 16" bayonet was found to be unweildy- try sitting in a chair with one stapped to your ammo belt- and too long for a fighting knife
There's also the "M1905E1" or cut-down Model of 1905 bayonets. These are 10" models and have two types of points, 'bowie' or 'spear'. The cut-off portions were used to make things like Victory Garden tools
There's also the so-called M1942 which is as near as I can tell, a differentiation that collectors came up with to ID a variation of the Model of 1905 made during 1942
try this link:
http://www.usmilitaryknives.com/bayonet_points.htm