Notice "See the full Casio range at your local music shop". That was actually correct in 1983 when I bought my MT65. The shop I bought it in specialised in home organs of the teak finished console variety which cost over £1000 but didn't sound any better than a top of the range Casio. It would be another couple of years before Casios and Yamaha keyboards started appearing in electrical shops
I think I first saw them at our department stores like JC Penney's, Sears and Wards, I don't remember seeing them at music shops which would have been at the local malls. Back in the 70's, every grandma had a cheap electronic organ, oddly they never made the switch to the better sounding Japanese Keyboards.