diff --git a/app/helpers/pdf_js_helper_decorator.rb b/app/helpers/pdf_js_helper_decorator.rb
index c1a4105..27f6105 100644
--- a/app/helpers/pdf_js_helper_decorator.rb
+++ b/app/helpers/pdf_js_helper_decorator.rb
@@ -33,8 +33,8 @@ def external_pdf(presenter)
   end
 
   def pdf_file_set_presenters(presenters)
-    presenters.select(&:pdf?).presence || presenters.select do |file_set_presenter|
-      file_set_presenter.solr_document["label_ssi"].downcase.end_with? ".pdf"
+    presenters.select(&:pdf?).presence || presenters.select do |fsp|
+      (fsp.solr_document['original_filename_tesi'] || fsp.solr_document['label_ssi'])&.downcase&.end_with?('.pdf')
     end
   end
 
diff --git a/app/presenters/hyku/work_show_presenter_decorator.rb b/app/presenters/hyku/work_show_presenter_decorator.rb
index ebe495c..0158d43 100644
--- a/app/presenters/hyku/work_show_presenter_decorator.rb
+++ b/app/presenters/hyku/work_show_presenter_decorator.rb
@@ -12,8 +12,8 @@ def part_of_label
     # OVERRIDE incorporates fallback to PDF.js viewer via fileset's import_url
     # see also pdf_js_helper_decorator
     def show_pdf_viewer?
-      return unless Flipflop.default_pdf_viewer? || !iiif_viewer?
-      return unless file_set_presenters.any?(&:pdf?) || pdf_extension?
+      return false unless Flipflop.default_pdf_viewer? || !iiif_viewer?
+      return false unless file_set_presenters.any?(&:pdf?) || pdf_extension?
 
       no_child_works?
     end
@@ -38,11 +38,17 @@ def no_child_works?
     end
 
     def pdf_extension?
-      file_set_presenters.any? { |fsp| fsp&.label&.downcase&.end_with?('.pdf') }
+      # Valkyrie works are apparently not getting label assigned, but earlier works
+      # used label for file name. Using a combination of both.
+      file_set_presenters.any? do |fsp|
+        (fsp.solr_document['original_filename_tesi'] || fsp.solr_document['label_ssi'])&.downcase&.end_with?('.pdf')
+      end
     end
 
     def iiif_media?(presenter: representative_presenter)
-      iiif_media_predicates.any? { |predicate| presenter.try(predicate) || presenter.try(:solr_document).try(predicate) }
+      # override TenantConfig to include pdfs so we can use the UV regardless of the config
+      predicates = (iiif_media_predicates + %i[pdf?]).uniq
+      predicates.any? { |predicate| presenter.try(predicate) || presenter.try(:solr_document).try(predicate) }
     end
 
     # Override Tenant Config