To answer, since you show you can obtain about any significant part needed, you should build one of course, if only for the satisfaction. Am glad to see you take detailed interest in your air guns and hope you continue and have good results. I do know there are air guns extremely accurate to a distance, and some cost thousands of dollars.
When I was young I had an old lever Daisy bb rifle. If the tension tangs were loose or otherwise let the cocking lever hang down after being cocked, pulling the trigger would cause the lever to come home with a finger crushing force. In later years I wondered if that was just mine, and if not, how did they survive the lawsuits?