How about ARP fasteners . They have about anything that you might need . Also , try Summit Racing. Either one will go out of their way to help you to get what you need.
Did you take a look at the parts diagram?...https://alpha-sports.com/massimo_parts.htm?q=massimo-parts I suppose there may be a unique situation that only a 1 off bolt or screw may work, but everything I see on the parts diagrams are standard metric bolts. They are after all trying to minimize costs, and creating unique hardware hardly seems productive.