"Stebel" trumpets that go with a "Marchal Stidor" compressor. These came off a 250GT coupe
These Marchal Stridor horns are mounted in Parker Hall's 250GT Pininfarina
Series II Cabriolet #2703
These FIAMM Horns come off a Series III GTE. I don't believe the finish
on the horns are correct as it looks like the previous owner had some kind
of plating done to the pot metal trumpets. The two colors that I've seen
on these FIAMM horns are a candy-apple-red or a sliver/gray paint. The
trumpet diaphrams are Hamertone grey.
Although I don't think I got the color right when I painted my trumpets,
but here's an idea on how the translucent red should look for the red painted
horns. I believe they should have a little more blue making it more scarlet
in color.
Here are some more pictures of horns for various cars.
These three pictures are from SN 8755 which is Kerry Chesbro's Series
II 330GT 2+2
The Horns pictured below are from Mike Plechaty's Series I GTE 2553.