Was watching the first Batman serial on TCM this morning. It was produced in 1943. In episode 8 Batman and Robin are towing a teardrop trailer with a Buick touring car. The trailer looks like a Kaycraft Kampster as pictured in the design library. It was 4 years too early to be the 1947 Teardrop for Two. You can check out the series by googling Batman Serial 1943. Fun stuff.
Jerome