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

Yes

The only difference between the use of "mil" in Brazilian and Continental Portuguese is pronunciation. In Brazil, the "l" at the end of a word is typically vocalized, making the word sound like "miu" ([miw]). In Portugal, the "l" is pronounced as a standard or dark "l" ([mil]). The meaning, spelling, and grammar are identical.

Brazilian Portuguese

1. Eu ganhei mil reais no sorteio. (I won a thousand reais in the raffle.)
2. Tem mil pessoas esperando na fila. (There are a thousand people waiting in line.)
3. Ele já leu mil livros. (He has already read a thousand books.)
4. Preciso de mil reais para viajar. (I need a thousand reais to travel.)
5. Ela postou mil fotos no Instagram. (She posted a thousand photos on Instagram.)

Continental Portuguese

1. Eu ganhei mil euros no sorteio. (I won a thousand euros in the raffle.)
2. Há mil pessoas à espera na fila. (There are a thousand people waiting in line.)
3. Ele já leu mil livros. (He has already read a thousand books.)
4. Preciso de mil euros para viajar. (I need a thousand euros to travel.)
5. Ela publicou mil fotos no Instagram. (She published a thousand photos on Instagram.)