What most likely happened, to cause that rattle, was the speaker was overdriven - the voice coil former struck the back plate and deformed.
To fix it, the repair shop would remove the cone assembly by ungluing it from the surround (and spider attachment to frame), something like pictured...
....and re-rounded the bent former (center of pic). When they re-glued the cone assembly to the surround, they did a crappy job.
Maybe, maybe not. Unfortunately, there is only one way to tell.
However, if you drive your speakers hard enough to damage the VC former in the first place, you will probably exercise that glue joint on the suspension enough to find out sooner, rather than later

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cheers,
AJ