yes you can.
the datasheet for the LCD controller will contain the available operations and their bit patterns you have to send.
I have just finished my first library for a 128x64 LCD so I'll tell you this now, if you haven't used an LCD before and understand the concepts, creating a library from the datasheet is very challenging and time consuming. I recommend using the library you have, then when you have more experience, create your own.
On the other hand, if you have the time, strong coffee, and the datasheet go for it.