Yes, this is emphasised in the *Muhaj al-Daʿawāt*.
فلما أصبح أبو جعفر ع بعث إلی فدعانی فلما صرت إلیه و جلست بین یدیه دعا برق ظبی من أرض تهامه ثم کتب بخطه هذا العقد ثم قال یا یاسر احمل هذا إلى أمیر المؤمنین و قل له حتى یصاغ له قصبه من فضه منقوش علیها ما أذکره بعده فإذا أراد شده على عضده فلیشده على عضده الأیمن و لیتوضأ وضوءا حسنا سابغا و لیصل أربع رکعات یقرأ فی کل رکعه فاتحه الکتاب مره و سبع مرات آیه الکرسی و سبع مرات شهد الله و سبع مرات و الشمس و ضحیها و سبع مرات و اللیل إذا یغشى و سبع مرات قل هو الله أحد فإذا فرغ منها فلیشده على عضده الأیمن عند الشدائد
*Muhaj al-Daʿawāt wa Manhaj al-ʿIbādāt*, p. 39
… The next morning, Abū Jaʿfar (peace be upon him) summoned me. When I came before him and sat in his presence, he called for a piece of gazelle hide from the land of Tihāma. Then he wrote this talisman in his own hand and said:
“Take this to the Commander of the Faithful and tell him to have a silver tube made for it, with what I am about to tell you engraved upon it. When he wishes to fasten it to his arm, let him wear it on his right arm. He should perform a thorough ablution and pray four rakʿahs. In each rakʿah, let him recite Sūrat al-Fātiḥa once, Āyat al-Kursī seven times, شهد الله seven times, وَالشَّمْسِ وَضُحَاهَا seven times, وَاللَّيْلِ إِذَا يَغْشَى seven times, and قُلْ هُوَ اللَّهُ أَحَدٌ seven times. When he has finished praying, let him fasten it to his right arm in times of hardship and distress. By God’s power and strength, he will be kept safe from whatever he fears and seeks to escape. When he fastens it to his arm, however, the moon must not yet have entered the sign of Scorpio. And should he fight the Byzantines or other kings, he will prevail over them by the blessing of this talisman.”
It is related that when Maʾmūn heard the Imam describe all these virtues of the talisman, he resolved to wage war against the Byzantines. God Most High granted him victory over them, and he gained abundant spoils. He never went into a campaign or battle without wearing this armband, and God, through His grace, supported him and, by His will, granted him victory. Truly, God brings it to pass through His power and strength. …
*The Etiquette of Travel in the Culture of Supplication* (translation of *al-Amān*), p. 175