By default, If no pom is specified during deployment of your 3rd party artifact, a generic pom will be generated which contains the minimum required elements needed for the pom. In order to disable it, set the generatePom parameter to false.
mvn deploy:deploy-file -Durl=file:///C:/m2-repo \
-DrepositoryId=some.id \
-Dfile=path-to-your-artifact-jar \
-DgroupId=your.groupId \
-DartifactId=your-artifactId \
-Dversion=version \
-Dpackaging=jar \
-DgeneratePom=false