Depends on what you're trying to accomplish.. If this is a key to an apartment or dorm room and the landlord or school wants another $100 for a copy of a key because they want to discourage people making keys for room mates who are not on the lease, or for girlfriends, then taking apart their lock and removing pieces of it in order to make it just a Schlage and not a Schlage Primus is probably not a good karma thing to be doing.
That said, it all depends on if the key you have is a C keyway. I suppose if you took out the sidebar and the sidebar pins and springs, yeah, I guess you could copy the key cuts to a normal blank but you'd be reducing the lock's security.. If the lock cylinder is a mortise cylinder and is your lock to be replacing or messing with then it's probably cheaper and faster to install a normal Schlage and make all the spare keys you need.
Hope this helps, and please don't do things that are going to get you in trouble with the landlord or university.
My spidey sense is going off the hook on this one.., just sayin...
Squelchtone
If all else fails, try this locksmith in your area:
http://www.andersonlock.com/