The answer (as usual...) is "it depends". There are some amazing pieces of lettering which are all the more interesting because of the mistakes that happened. One of these, very local to me, is Nottingham Gaol. I don't know what the favourite expletives were in the nineteenth century, but I suspect the stonemason will have used a few!
If you want to see this for yourself, it's on High Pavement in Nottingham, just along from the Galleries of Justice.