Some meters have a ’peak hold’ feature, others have a fast response/slow return so it’s easier to see values and peaks.
Which products are you referring to? I’m not aware of any analog meters fast enough to show peak.
You can also find 'peak' or 'max' on SPL meters, and calculate from your 'avg' (to ascertain how many watts were needed for those peaks based loosely on your speaker's sensitivity.
How do you back into it when the rated sensitivity is only from 300Hz - 3kHz? Maybe I'm not seeing something.