It will work okay unless the cover will be handled roughly, or extensively.

Thanks Don. Came across a black self etching primer made by Eastwood
Company suitable for bare aluminum and called them. They said it's
hazardous but there is no HAZMAT shipping fee and a respirator is not
required, just use in a well ventilated area. Couldn't find a MSDS.
They also said if a flat black finish is desired then the primer is all
that's needed. Sounds good to me....Anybody familiar with Eastwood's
self etching primer or products? Their chassis black seems quite
popular.