MP3 Encoding in 5.2
 

I searched for an answer to this, but couldn't find a relevant answer...

In 5.13, I was using the WinAmp LAME VBR as my encoder, after upgrading my plan was to continue doing the same, however the only MP3 encoder I see is 'MP3 Encoder v1.3' and when selecting VBR, it always copies at the VBR minimum.

Is this encoder actually using the LAME encoder?

Yes, Winamp has always used the LAME Encoder, from 2.95 to 5.0 to 5.21

Winamp 5.13 used Lame_Enc 3.96.1
We upgraded to Lame_Enc 3.97b2 for 5.21

From the 5.2 whatsnew
* Fixed: [enc_lame] bit reservoir
* Fixed: [enc_lame] cutoff of last frame
* Updated: [enc_lame] LAME 3.97b2

And as before, we always recommend to use the --alt-presets for vbr
eg. --alt-preset standard // --alt-preset fast standard