Yes!
However, you will notice that the Deploy Dev Environment button is not available from the UI of your newly created Preview Environment. This is because we still consider them as different spaces than regular Namespaces, and we do not expect the deployment of additional services to be a part of a Preview Environment namespace.
But you are able to achieve this through the use of the Okteto CLI. There are two different approaches you can take:
cd <additional service repo>
okteto ns use <Preview Env namespace name>
okteto deploy
Or
cd <additional service repo>
okteto deploy --namespace <Preview Env namespace name>