Last week WW was updated to have enhanced support for Goldsource. Among the changes were fixes for invalid SMD files when the model had a Skin modifier and for all sequence SMDs exported from WWMT.
Now those SMDs are all correct.
Also, WWMT will now create a Goldsource compatible QC file and compile to Source. Here are the docs and considerations for this: http://dev.wallworm.com/document/177/exporting_wwmt_models_to_goldsource.html