No not at all. It really depends on where you are going and the quarry.
There is ammunition out there for all guns and configurations so you won’t need to buy a new gun, at least to start with.
For those of you with only 23/4” chambers, use Bismuth or Tungsten in the appropriate shot size for the quarry you seek. If you are using the BASC permit scheme, a friendly ‘fowler may lend you a more suitable gun for the flight.
There is definitely equipment that will make you more comfortable when wildfowling. Take a look at our What to Wear when Wildfowling blog to find out more.