Continuity mistake: When Elliot and The Devil (Liz Hurley) are in Alison's bedroom, Liz tells Elliot that Alison is in the shower. Elliot goes to take a look, but notice the bed in the middle of the room. We see a shot of him and the bed, a shot of Liz then a shot of Elliot walking to the bathroom. So, in reality, Elliot walked through the bed to get to the bathroom, but it is back in the next shot.
Continuity mistake: When the Devil is a substitute teacher, the position of the big pile of apples on the her desk changes between shots. (01:01:40)
Visible crew/equipment: When Elliot, as a drug lord, runs to the plane and hangs off of it as it takes off, in one shot behind him you can see the whole camera dangling down. (00:34:25)
Other mistake: When Elliot the genius homosexual and Allison arrive at his apartment he hangs her wrap on the arm of the statue. He then begins to take off his overcoat and hangs it on the other arm. There is a cut to another angle and the coat is already hung on the arm and he is sliding out of it. There was not enough time for this transition to happen. (01:02:15)
Continuity mistake: When Elliot is in the Devil's office, the Devil goes over to a side cabinet, and picks up an apple. Next to the apples is a vase of roses. The position of the roses changes from when the Devil goes to pick up the apple, to the next shot, when she walks over to Elliot. (00:21:40)
Continuity mistake: Brendan Fraser's tie seems to magically disappear every time he is warped back into the present time. Watch from the beginning to about the middle of the movie, his tie is gone and his shirt bottom opens.
Continuity mistake: When Elliot is the Colombian drug dealer and is having an argument with his wife, she throws a glass of some liquid at him but it hits the door and the liquid splashes across the door. She then throws something else at him which also hits the door, but the door is now completely dry.
Continuity mistake: In Elliot's basketball player wish after the game you can see the sweat/water dripping on his face only when the camera is on him. When the camera focuses off him it stops only to magically appear when he starts speaking.
Continuity mistake: The Devil gives Elliot a pager and she tells him that if he wants to get out of his wish he should dial "666". In some wishes he presses the "6" three times and is transported out, in others he presses the "6" three times and then presses another button and is transported out and in the sensitive guy wish he presses the "6" four times.
Answer: It definitely is a Montegrappa Oriental Zodiac pen, this brand has been making pens in Italy since 1912. I am not sure which of the three red pens in that collection (Oriental Zodiac) is the one seen in the movie, but given its association with the devil, my guess will be it is the Ox fountain pen.