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

No.

While the spelling, grammar, and dictionary meaning of "postal" are identical in both Brazilian and Continental Portuguese, there are differences in typical usage. In Brazil, "postal" is primarily used as an adjective (e.g., serviço postal, endereço postal). When referring to the physical object, Brazilians rarely use "postal" as a noun, preferring the term cartão-postal. In Portugal, "postal" is very commonly used as a standalone noun to mean "postcard." Additionally, regarding addresses, Brazilians use the acronym CEP (Código de Endereçamento Postal), while Portuguese people use Código Postal.

Brazilian Portuguese

1. O serviço postal está em greve. (The postal service is on strike.)
2. O endereço postal está incorreto. (The postal address is incorrect.)
3. O CEP é o código postal. (The CEP is the postal code.)
4. O envio postal é lento. (Postal shipping is slow.)
5. O selo é para o envio postal. (The stamp is for postal sending.)

Continental Portuguese

1. O serviço postal está em greve. (The postal service is on strike.)
2. O endereço postal está incorreto. (The postal address is incorrect.)
3. O código postal é essencial. (The postal code is essential.)
4. O envio postal é lento. (Postal shipping is slow.)
5. O selo é para o postal. (The stamp is for the postcard.)