This is a M4 bolt modified chin front piece for this full size Halo Helmet.
Add 4 of M4 x 12 ( or shorter ) socket head bolts for detail to chin piece.
As there were artifacts in the slice from Makerware, the STL file has been flipped and reprocessed through netfabb ( again ).
Examination of output appears to show this has addressed the issue.
Print will be rerun and checked.