I imagine the hull of that kit is indeed cast in zamac. I don't know that "white metal" actually has any specific technical definition; I tend to use it whenever I'm talking about a soft, silver-grey casting metal. That's probably sloppy use of the language on my part.
I'd forgotten about the brass deck pieces. I'm not quite sure why the company chose that material - but to each his (or her) own. It is indeed different.
We've had some interesting discussions about the various Victory kits here in the Forum during the past few months - largely due to the efforts of our friend Michel.vrtg, who surely can now claim to be the reigning authority on the subject. Here's an example: http://www.finescale.com/FSM/CS/forums/610184/ShowPost.aspx
Identifiying the scales of the various kits turned into something of a project. Apparently the people responsible for the boxes and instruction sheets had only the vaguest notion of the concept of scale. It turns out that the Airfix kit (the larger of the two Airfix kits, that is) is on about 1/171 scale, and the Revell one is about 1/220. (If the Revell one were indeed 1/146 and the Airfix one 1/180, the Revell kit would be the larger of the two. That obviously isn't the case.)
I have lots of pleasant memories of both those old kits. I agree with Chris Hall that Airfix did a better job on some of the details - notably the upper deck stanchions and the figurehead. But I continue to think there's something seriously wrong with the shape of the Airfix kit's bow - an area that Revell got right. I also have trouble reconciling myself to Airfix's approach to the guns on the middle and lower decks, where the gunports are represented as countersunk squares and the "guns" are just stumps. Revell didn't have the nerve to provide separate pieces for all 102 (or 104, depending on which source you believe) guns, and molded most of the portlids shut. But the guns that are included in the kit are full-length, complete with carriages.
If I were to rate the Victory kits with which I'm acquainted (not all that are on the market, by any means), the list - from high score to low - probably would be as follows:
1. Heller 1/100. It's got some problems - most notably the configuration of the forecastle bulwarks - but generally it's a fine basis for a scale model. And in my opinion Heller probably was right to omit the elaborate entry ports.
2. Revell 1/220, in an almost dead tie with:
3. Airfix 1/171.
4. Skytrex 1/700. This, incidentally, is the only one that does have raised forecastle bulwarks.
One other kit unquestionably belongs very high on the list: the CalderCraft/Jotika wood kit, on 1/72 scale. I haven't actually seen that one - and given its price of over $1,000 I rather doubt that I ever will - but the photos and web descriptions make it clear that it's a first-rate kit.