The gmod_83a.exe file you have requested: Garry's Mod / Half-Life 2 Garry's Mod V8.3A - 7.44mb is not available. Perhaps try browsing all files for the game Half-Life 2 and upload any files you want to share or are missing. This is the only information we could locate:
This version of Garry's Mod allows you to spawn NPCs, play HL2 Single player and adds icons to the spawn menu to make things a bit easier. Check out the full changelog below. Enjoy!