The 2 indicates that it has a weight of 2 pounds.
Actually, you missed the row. The blowgun weights 2 pounds. The dart has a weight of * which means 10 of them weight 1 pound. Just in case you wonder when it comes to other items, ** means this weights so little that you can carry an unlimited amount with you.
The S says that it is a small item?
The 1d3 and 1d2, are they damage dice when used to attack small/medium and large enemy types? (respectively)
I'm not sure what the P means for the Type6 means
That the damage type is Piercing damage. Other weapons do Bludgeoning and/or Slashing damage. Note the dash when the weapon itself does not do damage, like a bow or sling. Only the ammunition is marked for damage type.
The column "factor" is a misprint in your table and actually reads "Speed Factor". That's the value that gets added to your initiative roll to determine who acts first in combat (See chapter 9: Combat, paragraph "Initiative"). The higher the number, the more cumbersome is the weapon and the more time is needed to hit someone with it. For example you can stab someone with a dagger real fast, while taking a swing with a twohanded sword takes time. The guy with the dagger is most likely going first in any round of combat.