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

No

While the spelling, grammar, and core meaning of "montaram" are identical in both dialects, there are differences in pronunciation and typical usage.

In terms of pronunciation, Brazilian Portuguese is more syllable-timed, with clearly articulated, "open" vowels. In Continental Portuguese, the language is more stress-timed, leading to significant vowel reduction; the unstressed "a" in the final syllable of "montaram" is often neutralized or nearly swallowed, making the word sound much more "clipped." In terms of usage, while "montaram" is perfectly understood in Portugal, Portuguese speakers often prefer different verbs or nouns in specific contexts (e.g., using elaborar for plans or roupeiro for wardrobes).

Brazilian Portuguese Examples

1. Eles montaram o guarda-roupa ontem. (They assembled the wardrobe yesterday.)
2. As crianças montaram a barraca no jardim. (The children set up the tent in the garden.)
3. Os cavaleiros montaram os cavalos ao amanhecer. (The riders mounted the horses at dawn.)
4. Eles montaram um plano para o feriado. (They put together a plan for the holiday.)
5. Eles montaram o palco para o show. (They set up the stage for the show.)

Continental Portuguese Examples

1. Eles montaram o roupeiro ontem. (They assembled the wardrobe yesterday.)
2. As crianças montaram a tenda no jardim. (The children set up the tent in the garden.)
3. Os cavaleiros montaram os cavalos ao amanhecer. (The riders mounted the horses at dawn.)
4. Eles elaboraram um plano para o feriado. (They elaborated/put together a plan for the holiday.)
5. Eles montaram o palco para o espetáculo. (They set up the stage for the show/performance.)