when you say "Config", do you have something special in mind?
Technically it's not a problem to run AEM Sites and DAM in parallel on the same instance(s). There might be other reasons (technical and non-technical ones) not to do that, that there a lot of customers out there which run AEM Sites and DAM in parallel.
To actually address your question and concern, you should get in contact with your implementation partner; they know the existing site solution best and can say if the sites implementation has side-effects to any DAM functionality. But to be honest I would be surprised if there are any. Sites and DAM have been developed to work side-by-side.