Absolutely. The sxs folder is not product-key specific. You can copy microsoft-windows-netfx3-ondemand-package.cab to a USB drive and run the DISM command pointing to C:\sxs on your offline machine.
After running your offline installer, confirm success: Absolutely
Cause: The source (ISO) is corrupted or the path is wrong.
Fix: Remount the ISO. Ensure the CAB file exists in \sources\sxs. Try copying the entire sxs folder to your desktop (C:\sxs) and change the source path to /Source:C:\sxs. After running your offline installer, confirm success: