I think you could get the accurate trim on there. Depending on how he constructed the helmet it seems you might have to glue it on.
There was an older post about someone finding an adhesive rubber door trim at an auto parts store and it seemed to work good on FX buckets.
That looks like the same thing I have. I paid about $15 at a local motorcycle dealer store. My FX fits in it without issue. I need to get my Garrison and FISD patches on it though.
There is the list of all TK #s in use, you can search through the list to make sure what you want isn't taken. The application says pick 5 #'s in case one is taken.
I think this might have come up before
I know, I was going for the more pop culture/slang based definition.
No offense was intended to anyone who suffers from either schizophrenia or multiple personality disorders.