The quality and rigidity of PB 5x0 case plastics varies significantly out in the wild - I'm with unity and would suggest just choosing another with good pics online.  You'll be there for a day and an age modelling and printing a rough equivalent which is a waste of time when original parts are easily obtained.  

Most 5x0 have brittle plastics which snap and scratch easily, while others have a slightly darker plastic (less use/UV exposure?) which holds up well to this day.  Look for a 540/540c specifically.