VOCALOID3 voicebanks cannot growl within the VOCALOID3 and VOCALOID4 editors as they do not have access to the GWL parameter nor do they have data for it.

However as of VOCALOID5 and VOCALOID6, all voicebanks from VOCALOID3 onwards have access to the default growl settings included with the V5/6 editors. So she could very well have been rendered in the V5 or V6 editors and that's what you heard.

Also as of the PIAPRO CHARACTERS SUPER PACK for VOCALOID4 and Piapro Studio, MEIKO SP can use the GWL function in V4.