On 68 Chevelles the hidden or "recessed" wipers were an option. The 68 Malibu, which I no longer have, did not have them.
The hidden wipers have an articulated wiper arm on the drivers side. Look at the drivers side wiper arm drive gear?, if it has a small post beside it (about 3/16" diam. x 3/8" high) you have the hidden wiper transmission.