Did legion workshops make money?

[richsc]

The 20th legion had a tile workshop that covered four acres near Chester. Other than producing endless roofing tiles to replace the stuff drunken legionaries broke, who did they sell it to? Were the legion's factories profit centers? Did they displace the locals on price and quantity?<br>
We had had some discussion earlier on the Romans' effect on the local economies: were these local workshops significant or were they just for local consumption? <p></p><i></i>