I've known about this for a while before actually reading Might is Right, (read it last night; excellent) but Anton LaVey does indeed lift whole lines from it in the Book of Satan.

The paperback edition I have of The Satanic Bible makes no mention of Might is Right.

Can anyone confirm for me that older editions of The Satanic Bible do contain any reference to Might is Right as an inspiration and source?

I find it highly unlikely that the Doktor would plagiarize; the fault more likely seems to be with the publishers omitting the relevant notation, if there was any.