yes, I oil with the pen and it works very well. It is very useful for getting inside the movement such as under the balance.
The import thing is to only dot the tip and not immerse it. Otherwise, of course it would hold way to much and muck up the movement. To prevent this I use the crystal in the picture to hold only a single drop.
Sometimes I use fine sewing pins too. Only problem I have there is they tends to slip out of my finger tips. Most be the result of all thos years hanging out in the weeds of the Meadowlands!