The polished rounded versions are powered by the 10xx series, whereas the earlier versions with the radial brushed finish are powered largely by the 5xx series and the 6xx hand-wind movements, which, from a strictly collectible point of view are the ones to go for.
Some years ago, a truckload of independent parts including cases, dials and hands for the 10xx series powered models came on to the internet, and unscrupulous operators pillaged 10xx movements from old bangers, fitted them to the new cases and dials and sold them as NOS. Hence, in the Dynamic Collecting fraternity, great care is taken when buying them, requiring the movement to be removed from the case front for inspection. Thus they are not so collectible.
Cheers
Desmond