Generally, HP does not make changes over OOTB solutions design (mean workflows and request fields). But if there is a change occur in OOTB solutions design (e.g. HP add a new field in pfm-proposal), the change reflect to your request.
Because of that you should copy Request Type, Request Type Header and Workflow from OOTB and create your own solution.
Even if do that, if HP change Field Group Types' fields, so it will reflect to your solution too. It is inevitable.
PS: If the post resolves your issue, please KUDOS the professionals and mark it as Accepted Solution.
IT Governance Professional & PPM Solution Architect