Yes, 12.07 contains USBAUDIO.SYS.
... and obviously nothing else.
the usbaudif.dll and usbwav.dll I have installed are:
[C:\mmos2\dll]bldlevel usbaudif.dll
Build Level Display Facility Version 6.12.675 Sep 25 2001
(C) Copyright IBM Corporation 1993-2001
Signature: @#Lars Erdmann:10.234#@##1## 18 Apr 2020 12:42:31 Laptop
::::::@@USB Audio 1.0 and 2.0 VSD
Vendor: Lars Erdmann
Revision: 10.234
Date/Time: 18 Apr 2020 12:42:31
Build Machine: Laptop
File Version: 10.234
Description: USB Audio 1.0 and 2.0 VSD
[C:\mmos2\dll]bldlevel usbwav.dll
Build Level Display Facility Version 6.12.675 Sep 25 2001
(C) Copyright IBM Corporation 1993-2001
Signature: @#Lars Erdmann:10.234#@##1## 18 Apr 2020 12:42:50 Laptop
::::::@@Filter IO Proc and MULAW/ALAW Codec for USBAUDIO
Vendor: Lars Erdmann
Revision: 10.234
Date/Time: 18 Apr 2020 12:42:50
Build Machine: Laptop
File Version: 10.234
Description: Filter IO Proc and MULAW/ALAW Codec for USBAUDIO
Nothing else
About 12.07, here is wpi archive view.