Charles, Sunshine resin kits are the only accurate HO Swift meat reefers for the period you mentioned.
For the time period: Red Caboose makes an accurate plastic model of a Mather meat reefer. Atlas has a nice plastic model based upon a Cudahy car from 1925. To move further from accuracy, the MDC 36' old time reefer or the Varney (LifeLike) 37' wood reefer can be kitbashed into generic wood meat reefers.
