Red dial IIIf bodies were made later, from #615000 on up. Other than cosmetic differences, the shutter was improved and the shutter speed progression was different: T, 1, 1/2, 1/5, 1/10, 1/15, 1/25, 1/50, 1/75, 1/100, 1/200, 1/500, 1/1000 & B. Some of the later RD bodies also had a modified film rewind mechanism. The self-timer was introduced during the run of the RD bodies, although BD bodies could be retrofitted with the self-timer by the factory. Otherwise, either one in good condition is a great shooter!