Create this below as a .cmd file and you can push from SCCM. Just remove the "path" and add your UNC path to the installer. This cmd will also create an icon to the users desktop. Same thing add your UNC path to the G2M icon. This is for the must recent update if you use an older one or an another new one comes out you have to just change the 4 numbers here it is "1216' this will change every new release.
taskkill.exe /F /IM "g2mstart.exe"
taskkill.exe /F /IM "g2mcomm.exe"
taskkill.exe /F /IM "g2mlauncher.exe"
start /wait msiexec.exe /i "Path" /quiet /norestart
"C:\Program Files\Citrix\GoToMeeting\1216\G2MInstHigh.exe"
powershell.exe -noprofile -command "copy-item '\\Path\GoToMeeting.lnk' -Destination 'C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup' -Force -Recurse"
powershell.exe -noprofile -command "copy-item 'Path\GoToMeeting.lnk' -Destination 'C:\Users\Public\Desktop' -Force -Recurse"
powershell.exe -noprofile -command "copy-item 'Path\GoToMeeting.lnk' -Destination 'C:\ProgramData\Microsoft\Windows\Start Menu\Programs' -Force -Recurse"