Could older airplanes be retrofitted with engines with chevrons?
The chevrons do not implicate a particular type of wing or airframe. However, the engine does need to be designed around having the chevrons, since they affect the performance as well as noise. And the engine design certainly can affect the design of the wing.

In reality, chevrons are more likely to be incorporated in an engine design from the start rather than retrofitted later. And a new engine design will probably be for a new airplane design. This could be a totally new plane like the 787. But it could also be a new derivative, like the 747-8 or the 737 MAX.

So while chevrons can be added to the engines on an existing aircraft model, it's much more likely that the aircraft model will be upgraded in other ways as well to accommodate the new engines. Adding chevrons is likely to be part of a design change large enough to justify changes to the aircraft as well.

However, these changes are not really specific to the engine having chevrons. Changes to the wing and airframe will be due to the inclusion of a new engine, not just the addition of chevrons.