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

Yes.

The only difference between the use of "guardou" in Brazilian Portuguese and Continental Portuguese is pronunciation. In Brazilian Portuguese, the pronunciation tends to be more "open," with vowels being clearly articulated and the rhythm being syllable-timed. In Continental Portuguese, the pronunciation is more "closed" and stress-timed; unaccented vowels in the surrounding words are often reduced or swallowed, which can make the word sound more clipped or more integrated into the preceding consonants.

Brazilian Portuguese Examples

• Ele guardou o dinheiro na carteira. (He put the money in the wallet.)
• Ela guardou o celular na bolsa. (She put the cell phone in the bag.)
• O menino guardou o brinquedo. (The boy put the toy away.)
• Ele guardou o arquivo no computador. (He saved the file on the computer.)
• Ela guardou o lixo na lixeira. (She put the trash in the bin.)

Continental Portuguese Examples

• Ele guardou o dinheiro na carteira. (He put the money in the wallet.)
• Ela guardou o telemóvel na mala. (She put the mobile phone in the bag.)
• O miúdo guardou o brinquedo. (The kid put the toy away.)
• Ele guardou o ficheiro no computador. (He saved the file on the computer.)
• Ela guardou o lixo no caixote do lixo. (She put the trash in the bin.)