Yes....i have wondered that, as the HQ-7 missile system, basically a Chinese updated version of the French Crotale, is a little bit long in the tooth now....still effective, but doesnt have the same capabilities as the newer AA missiles used by the PLAN today such as the HQ-16.
The 2 054's are a bit of an oddity, as they are still relatively young, modern, stealth Frigates......but are armed with a modest AA missile system. What will the PLAN do with these ships at a mid life refit?..........if it is deemed to expensive or difficult to convert to a VLS. Mind you Chinese naval planners would of known this, when conceiving the class, knowing that the 054A was to follow shortly.
One could say why did the Chinese produce the 2 054's in the first place, knowing a superior version was to be built soon after?