I see what you mean about that web-site K. It does appear to be authorative. However, all photos I've seen of these bombs, and an actual bomb casing, were a greyish colour, varying in tone (no doubt due to the colour printing processes, aging, dirt etc), between a light mid grey and the greyish green previously mentioned. I will admit though, that at least one period colour print I've seen has exhibited a slight bluish tinge, not that far removed from RLM76.
I've been looking for one source I used some years ago, without success, which described the colour as light grey, and I seem to recall using Medium Sea Grey to paint the bombs on, coincidentally, a Fujimi Bf110, about 25 years ago(!).