Rune's clothing is quite a bit different than his final version shown in Phantasy Star IV. He has a pull over shirt instead of a one that closes in front, lacks his black gloves, and wears smaller boots. Also missing is his brooch in the form of the common Esper symbol. This look has a more casual feel than Rune's final outfit. This alternate design is used in most sketches of Rune one can find in Phantasy Star Collection (Saturn) and Phantasy Star: Official Production Compendium.
You may view the gallery page for Rune Casting.