Override templates for one view page or block
Yes.

The pattern will be something like views-view-promotions--display_name.html.twig

See https://api.drupal.org/api/drupal/core%21modules%21views%21views.theme.inc/group/views_templates/8.2.x

Also, I recommend you activate Twig debugging (https://www.drupal.org/docs/8/theming/twig/debugging-twig-templates) to see actual suggestions.