Yes, that is a Phileas. Its a great pen, and generally considered a standard. I'm guessing you'll be happy with it. I'm would be happy with mine except SWMBO keeps "borrowing" it.
As the other poster wrote, it shouldn't be a problem (in fact, I've done this with my Phileas before) and some pens are designed for it. I'm sure someone will correct me if I'm wrong, but I seem to remember reading a review of a Churchill that said it went from a broad to a fine when flipped over. Nothing like utility!
“A shave, please, but don't cut my throat. I may want to do it later myself.”
- Casey Stengel