Vise IS the one for drilling.
Pen press is the one for assembly.
There are times when a clamp is used as a pen press (I have). If you would, I bet you can use the vise for assembly too. To confuse you more...I use an arbor punch as pen press now. [B)]
Tracy, just so we are on the same page, what I just posted on the Raffel is the pen vise and what I posted on the tool gloat is the pen press. Clear as mud?