Found it. It's more interesting than that(but more logical, tbh)
The transport container is angular, but the launch container is circular, and may very well be old one inside a new outer shell. Which is logical,because no one is going to change hundreds of land TELs without a good reason. This way they gain both conveniences of storage&fitting and compatibility,
Overall - I don't think retaining old launchers will be a big problem.
Previous refits were actually lighter (automatic magazines for rail launchers were complex and heavy). Here we're either adding weight(if trying to fit 48 forward), or cutting inside the ship with unknown complexity - it may very well be undoable.
Basically - if it's possible to achieve the necessary level of tactical compatibility (radars, ECM, coms, and new missiles) - I don't personally think 052Cs even need such a deep refit. They're quite modern ships as they're right now.