I just started work on the Heller Ariane kit. I notice the lower part of the core has a surface with small panels, and the instructions call for this area to be tan. Pictures sometimes show this a tan or off-white, others as a sort of bare metal surface. I thought at first the tan pictures might be showing frost from cold LOX or LH2, but most of the frost I've seen has been very white.
Anyone know what the material of that lower booster area is? Is it painted, or bare metal? When it is tan, is it paint or some insulation? From pictures showing a bare metal look, it looks more like stainless to me than aluminum (shades of the old Atlas!).