i just tried this with the example schema:
1) changed the "cat" field to have omitNorms="false"
2) edited solr.xml so there was a second <doc> with all the same data
except a differnet "id" and a doc boost of 2
3) restarted port, and reindexed solr.xml
...when i search on cat:search, i definitely see the docboost comeinto