Yes, You can add gallery component to post and select any available gallery you have created. In your case you have to put gallery component in all your posts with the gallery you need by selecting the gallery from component options.
We recently spoke with Joe Buonocore, CEO of Albright Labs, a development agency based in Albrightsville, PA, United States. As long-standing partners, Albright Labs has earned a special place within the October CMS community. Specializing in custom development, they choose October CMS as their preferred platform.