The 820 searchlight car was introduced by Lionel in 1931 and was cataloged through 1942. The earliest cars came with terra cotta platforms and brass lights. In 1934 the color changed to 45N green with nickel lights. The 1934 45N green is darker than the later 45N or accessory green. The darker 1934 color is shown below. All searchlight cars after 1934 have 45N green platforms. In 1940 the floodlights changed to gray painted die cast and the frame was changed to a dish frame to accommodate the newer style of trucks.
The Lionel 820 with die cast floodlights is almost impossible to find. The version with the darker accessory green platform and latch couplers is the next hardest to find. All other versions are quite common.
See also Lionel 2820 Searchlight Car