I have a pair of KLH Model 6's that are identical cabinet wise but the serial numbers are far apart....2398 and 31253....hard to think they were bought as a pair, perhaps the 31253 was a warranty replacement or a single was bought to replace a damaged cabinet......anyway these are in excellent shape for their age and I believe both these have the epoxied baffle common in the early models.....I also assume at least the lower serial number has the oil caps used early on, but not so sure about the later serial number.....they sound fine and like most others I don't want to tackle the recap if the oil caps are still good.....there is also the issue of cutting off the original grill cloth to reseal the surrounds and having to replace the grills....I have a later pair that has been recapped and resealed as well......I know there are varying opinions as to when the oil caps were phased out and I believe it was much after 31253 would have been built......can anyone shed any light here?