They're decimal values for the hexidecimal code for a monsters type, element and property.
I'm too tired to do it for you atm (it's 5:30am), but have a look at RMS and compare codes between similar mobs.
ghoul = 3211521 (H: 31 01 01)
First value is Property.
31 = Undead 2.
Second value is Size.
00 = Small, 01 = Medium, 02 = Large.
Third value is Race.
0 = Formless
1 = Undead
2 = Brute
3 = Plant
4 = Insect
5 = Fish
6 = Demon
7 = Demi-Human
8 = Angel
9 = Dragon
Edit: On a side note, the third argument is only 300 for regular mobs. MVP's are labeled 301