Answer
Yes — wrap the Deferred_Call, or the logic it eventually invokes, with Fnd_Session_API.Impersonate_Fnd_User('<target_user_id>') beforehand, and Fnd_Session_API.Reset_Fnd_User afterward, to temporarily change the session's effective user identity for the duration of that specific action. The same Impersonate/Reset pattern used elsewhere for running actions as another user applies directly to Deferred_Call-based background actions as well.