Here is a purple 145 CREB I acquired from Dee Willett in 1979. When I bought this from Dee, it had hand-applied white paint over the weak embossing, as shown in this picture. I can say with certainty that this white lettering has been on this insulator for at least 30 years.
Recently while perusing the CREB folder, I came upon this picture posted by Dave Wysoski:
This is a very similar shade of purple as my CREB, and the white lettering looks nearly identical to mine. Dave said he's had his CREBs for a while. I wonder if the same person applied the white lettering to both of these CREBs? Guess I'll ask Dave!