As Paul Drake helps the suspect up, a pile of stage money cascades out of the person's coat. Yet for some odd reason there is a single, genuine US $100 bill in Drake's hand. No effort is made to disguise the fact that the rest of the bills are bogus, and it is not part of the plot; it's just traditional stage money used in TV and movies of the period.
The murder weapon is a Colt New Service revolver, which Hamilton Burger describes in court as having been newly purchased. The New Service was, in fact, discontinued twenty years before this episode aired.