No. If a project manager has write access to the file they can modify any of
the project properties and activities within the file. The only things that
can be locked administratively would be baselines 0 -5 and the contents of
value lists (but not the selection of items from the list)
There are a few hacks which could work around this (separate files for each
phase perhaps?), but as a general rule, you have to manage this in some other
way than using tasks or project properties.
If you trust someone to manage a project (expending your organizations money
and people in the process) surely you can trust them with a project file? If
not, you have either not trained them or you have the wrong people.
-Jack Dahlgren