Hi Paul,
Unless something has regressed, objects pre-placed in a level have their construction scripts ran at cook/“package” time. They are solidified in the level during that process. This is to address the exact concerns you’ve brought up.
Dynamically spawned objects however will run their constructions scripts as they’re created. Events like BeginPlay, where some setup/initialization script can be placed will also be executed at runtime, so be mindful of that.
Are you seeing specific evidence that construction scripts for pre-placed level objects are being ran in cooked builds? Note that running the editor with -game is still an editor build, so expect constructions script to be ran there as well.