can anyone make a mod where the execution for the firearms is the red beta one from the extended executions mod by megahoff? 

The beta executions mod is up on Mod DB as Manhunt 2 Extended Executions. It's not just firearms, though. It restores almost every beta execution, if that's what you're looking for.

Go to "files" under the title, then download the mod and update. The other downloads for camera angles and weapons placement aren't necessary.

Download it easily on Moddb.