Depends on what "out of shape" is, (worn in?) and to what extent. I mean, if it's
visibly out of shape I wouldn't bother, it's very probably near the end of its life.
But you can easily find a Brooks on
eBay that's a few years old and doesn't really have any sign of being used much, so they're worth a go.
Plenty of CC members will have bought a used Brooks, I know Cyclops for one has a well-used, pre owned one that he likes. But "out of shape" to me conjures up an image of "knackered". Once the leather has stretched it can be prone to tearing / breaking at the nose end.