I'm creating a C# library and am going to expose a COM interface to it.

I understand the steps requried to do this, i.e. 

1. Ensure assumbly GUID is assigned, e.g:
`[assembly: Guid("dde7717b-2b75-4972-a4eb-b3d040c0a182")]`
2. Ensure COMVibile attribute is True
3. Put a GUID attribute on the class, e.g. `[GuidAttribute("4df74b15-d531-4217-af7e-56972e393904")]`
4. Register using Regasm.

My question is this. If I have a partial class defined. Do I need to add the `GuidAttribute` to both these classes? 

In fact, thinking about this, I'm guessing this question applies whatever the attribute (e.g. `Serializable`).

Any help would be appreciated. Thanks.