These models were introduced as kits by Precision Masters. Later on, PM sold them ready-to-run. Circa 2005, Red Caboose acquired the entire line of PM cars and released them (RTR) in Red Caboose packaging.
Generally speaking, Red Caboose splits production of their models between the US and China (just how much of what is done where varies by model and production run).
Here's what Red Caboose has to say about them -
Refrigerator cars as a whole gained acceptance in the mid to late 1800s (1880 +/-). All of these early cars were made of wood. Metal frames became common with wood bodies in the early 1900s and this general practice would remain until the 1930s when the first major production of all steel cars began. Many wooden cars were updated with steel ends and roofs starting in the 1930s until the cars were being retired in the 50s and 60s. This wood reefer depicts cars that had been upgraded with a steel roof and ends.