Is the word prateleira the same in Brazilian and European Portuguese?

Yes.

The word "prateleira" is identical in spelling, meaning, and grammatical function in both Brazilian and Continental Portuguese. The only difference is in pronunciation. In Brazilian Portuguese, the vowels are generally more "open" and clearly articulated. In Continental Portuguese, unstressed vowels are often "closed" or reduced, which makes the word sound more compressed or clipped.

Brazilian Portuguese Examples

1. Coloque os livros na prateleira. (Put the books on the shelf.)
2. A prateleira está muito cheia. (The shelf is very full.)
3. Eu limpei a prateleira ontem. (I cleaned the shelf yesterday.)
4. Tem um vaso na prateleira de cima. (There is a vase on the top shelf.)
5. Preciso comprar uma prateleira nova. (I need to buy a new shelf.)

Continental Portuguese Examples

1. Põe os livros na prateleira. (Put the books on the shelf.)
2. A prateleira está cheia de coisas. (The shelf is full of things.)
3. Limpei a prateleira ontem. (I cleaned the shelf yesterday.)
4. Há um vaso na prateleira de cima. (There is a vase on the top shelf.)
5. Tenho de comprar uma prateleira nova. (I have to buy a new shelf.)