Ref. 810A with Cal. 8541

I've been collecting vintage Omegas for a while but have always wanted an IWC dress watch. I have found this watch but have questions about it. It's listed as being from 1962 which I think is wrong because the "date your IWC" information states that movement was introduced in 1964 (although Dr. Ranfft states 1963), the same year as the serial number. I have found a SS version but not a similar gold. It appears to be correct but would appreciate confirmation from more knowledgeable members.Here's a link to photos.