Is it possible to modify the header in redwood themed parts of fusion?

Summary:

Hello,
We are trying to place an AppDynamics monitoring script in the global header of Fusion to create synthetic monitoring for it.

We are able to successfully inject it into the Fusion global header but cannot in pages that use Redwood. Does Redwood utilize a global header? If not, is it possible to modify all Redwood page headers at the same time?

Thank you

Content (please ensure you mask any confidential information):

This is similar to the script that we are trying to inject in the header of our Fusion pages:

<script charset="UTF-8" type="text/javascript">
// Record the start time for AppDynamics