Try looking at dmesg output and it should tell you what drive it was created as. Some Pen drives use partition 4 and others partition 1 so you will have to check this but usually no it is just partition 1 I think. So you would do something like this:
mount /dev/sda1 /mnt/pen
Now the pen directory under /mnt would need to exist. But you may want to check, it is possible RH is automatically creating a mount point and mounting it, you can find this out by typing mount as root at a prompt and seeing what comes up.
I am somewhat new to the Linux world, but at the same time I am learning the OS at an ITT campus. Doe sanyone know how to mount a pin drive in Red Hat?