Is it possible to switch graphic cards from one laptop to another?

I have an acer aspire 5810T and my sister has an acer aspire 5810TZG and some of the specs are different like my processor is better and her graphics card is better, but the design and shape of the laptops are the same. Its impossible to buy a new card and put it in a laptop because it wont fit but if the outside of the laptop is the same will it fit