Not sure I can give you a 100 % answer, but I can give you some info. One of my collecting parameters was to try to get one of everything Bob L listed for Topps baseball in the Standard Catalog from 1948 through 1994 when proliferation did me in. These things are in the Catalog.
I have a full set run 1984 to 1991, which is I think the last year they were issued. Initially called Gallery of Immortals in 1984, the name changed after that to Gallery of Champions. The sets all had 12 metal replicas of 12 player cards from that years set, In 1984 and 1985 the sets came in Bronze and Silver only. After that they added an additional aluminum set ( planet Munimula spelled backwards for you Tom Terrific fans). For the most part the sets were distributed in fake leather display cases which were velvet lined. The sets also came with a COA. Kind of nice actually
I have all the display cases and many of the COAs ( there was no case for the initial aluminum set in 1987 and those pieces came cello wrapped.
Each year one of the players in the set was also produced in pewter as a premium for dealers who handled the set. After I got the sets I started searching for the pewters. In running them down with an ebay search I started getting hits for players other than the ones that Bob L had listed in the catalog as existing in that form. I bought one and sent it to him and he determined it was a fake and listed information on them in the Catalog
Why anyone would bother to counterfeit these things is hard to fathom. But I never saw them marketed as silver. They were always listed as pewter. The ones I bought seemed to have a "seam" along the edge of the "card" while the real ones look like just one piece. Also, it seems more porous than the real ones in their makeup. Bob L describes them as cast rather than die struck. The one in the Catalog, Murphy, is one I sent him. I kept a few...because they are listed in the Catalog
I have never heard of fake bronzes, but if you want to send me one of your suspects I can compare it with my fakes, or if you would prefer I can send you one of my fakes for you to compare.
As a side note, and to fit this all back into pre 1980, Bob has listed another "fake" in the Catalog in the 1960 Topps section. He mentions 1950s to 1960s "Promotional Samples". The example pictured in the book, page 397 of the 2011 Book, looks like a 1962 mini Mantle with Promotional Sample stamped on a blank back. These were apparently "produced" by cutting out Topps card pictures from the Topps Team Surf books and pasting them on cardboard. They look somewhat like the 1975 and 1985 mini in size, but even smaller.
Bob says the fakes have "no collectible value", but since they made it into the Book I of course had to have some. So I searched for them and bought a few on ebay just to further complete my checklist
I also have some fake 1955 Topps baseball rings, and some 1977 Topps baseball Puffy Stickers....but that can be for another day