Credit to those whose posts gave me all the necessary information and programs to do this. Namely, those who've done this very same thing before. Sorry, in a hurry at the moment to post this, will credit by name later. Thank you to those concerned!
The latest stock ROM, v23A, made for the Verizon LG G Pad 8.3 model VK810.4G, also called "altev" in KDZ format, which is flashable via the Windows utility "LG Flash Tool 2014 - Tools Offline KDZ Flash Rom for LG".
The KDZ file is in a zip, so you'll have to extract it. It is NOT a flashable zip.
Any current and future files for this and other devices will be available in my section on Android File Host.
I obtained the KDZ file for 23A by:
1. Installing the latest LG drivers for Verizon LG_VZW_United_WHQL_v2.18.0.exe (I'll link later).
2. Finding and running LGMLauncher.exe (I'll link later).
3. Connecting the VK810.4G to the PC via USB and choosing Internet-Ethernet mode.
4. Opening the menu in the upper right corner and choosing "Update Recovery".
5. When the download and update on the tablet were done, then I could find the KDZ file in "C:\ProgramData\LGMOBILEAX\Phone".