This has, as far as I remember, also been discussed before. I was sailing for some years on Mowinckels Gearbulk-vessels, and on all papers, drawings etc. which we had, they were referred to as bulk-carriers. (Open-hatch bulk-carriers). On one of them we were engaged in coal-transport between Baltimore and Sines,Portugal. With almost 40000 tons of coal inside holds I will not call them General Cargo.
It seems like it is in later years, that they has changed from bulkers to General Cargo. I also have some copies of Clarkson Bulk Carrier registers, they are listed there, and I can't understand if they should list General Cargo-vessels in there