usualy mildots are - for every dot is 1, now the only thing i can think of relating to 3/4s is the clicks on top of the scope for the sight adjustment, but usualy thats in MOA and you want something near 1/4 - also your mildots can change value depending on if they are on the front focal plane or not because then sometimes you will also magnify the mildots and they will always mean 1 mil dot, but if they dont magnify with you then you have to adjust them in your mind such as 2x, every dot is now 2
correct me if im wrong (^_^0) im new at this also
but as for as army or USMC style i dont know what your talking about...or if they exist
USMC style the space between each mildot equals 3/4 MOA... which would be .75 inches at 100 yards... or an inch and a half at 200... so tape a quarter to a piece of paper at 100 and see if it fits between the dots.
Each Mil Dot is .25 MOA in diameter... the space inbetween each Mil Dot is .75 MOA (for the USMC Mil Dot)... so draw a line that is 1 MOA long on a target... place the target at 100 yards... and see if it lines up. Or... you could just call the information center for the company who manufactured your particular scope and ask. Most Mil Dots are in the USMC configuration however... so chances are it is USMC configuration.