I also found them the seashell, in the 1942 Special Equiptment "Silver Book".
http://i391.photobucket.com/albums/oo352/46Canopy/scan0002.jpg
http://i391.photobucket.com/albums/oo352/46Canopy/scan0001-1.jpg
And they are also in the 1941 Chevrolet Directory "Silver Book".
kingisomer, I am short on 1946 Accessory books, very hard to find. Same as the salesman data hand book for 1942 and 1946.
I have some GMC Accessory books, but will need to dig them out. I will keep looking for them as well.
So, in summary, the trumpet horns for sure were avail in 1946, the seashell 1941-1946. I kinda like the trumpet horns, as JiMerit said, they have a bracket that crosses the radiator support rods, and have not seen the town and country switch, cept in books. Looks like a setup to look for. 46 Texaco, want to dispose of those trumpet horns?
Dale