I don’t think Allred is dumb enough to take part in the forgery. But she IS willing to look the other way and submit it as evidence KNOWING it’s a forgery.
I can see Allred saying....”Is it a forgery...I don’t want to know”. That clears her.
I was only outlining the possibilities. As Sherlock Holmes said, first you make a complete list. Now go and prove which can be taken off and after you’ve done that, what you have left no matter how implausible has to be the truth..... or something like that.
I can see Allred saying to Beverly.....”If it’s a forgery, I don’t want to know”.