I was just thinking
I am completely unfamiliar with the range rules associated with CAS or other sanctioned events
It is possible that you can make your Remington "legal" temporarily by installing something that you would make to complete the trigger guard.
If the rules state that the trigger guard must be unmodified, I guess you are out of luck. On the other hand if the rules state that the trigger guard must completely surround the trigger, then you might think about fabricating a part that could be screwed in place to make the pistol acceptable at least until the real thing arrives.
Again I apologize for my lack of familiarity with the rules. Perhaps you have already thought of this approach.
My reading of history convinces me that most bad government results from too much government. Thomas Jefferson