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

Yes

The spelling, meaning, and grammatical function of "três" are identical in both Brazilian and Continental Portuguese. The only difference lies in pronunciation. In many Brazilian dialects (such as in São Paulo or Minas Gerais), the final "s" is pronounced as a clear [s] sound, as in the English word "bus." However, in Rio de Janeiro and other coastal regions, it is often pronounced as [ʃ] (the "sh" sound). In Continental Portuguese, the final "s" is almost always pronounced as [ʃ].

Brazilian Portuguese Examples

1. Eu tenho três irmãos. (I have three brothers.)
2. Vou pegar o ônibus às três. (I am going to take the bus at three.)
3. Ele comprou três biscoitos. (He bought three cookies.)
4. São três horas da tarde. (It is three in the afternoon.)
5. Tem três pessoas aqui. (There are three people here.)

Continental Portuguese Examples

1. Eu tenho três irmãos. (I have three brothers.)
2. Vou apanhar o autocarro às três. (I am going to catch the bus at three.)
3. Ele comprou três bolachas. (He bought three cookies.)
4. São três horas da tarde. (It is three in the afternoon.)
5. Há três pessoas aqui. (There are three people here.)