I am trying to build dragon"s 1/35 Panther Ausf D Kursk version kit. I like to depict one of the earlier vehicles without zimmerett, with the spent shell casing hatch on turret side, no rain gutter above the pistol port and shell hatch.

Dragon gives two style of circular fan cover. One with a radial pattern cast grid, one with a swirl pattern cast grid. Which is appropriate for a relatively early Panther D?

What is this about the filler caps and the cutting of the castings ?

Are you familiar with Jentz's Germany's Panther Tank the quest for combat supremacy ?
Is this info in there ?

The information I have matches what Gerald said, the swirl fan cover was before the straight and would be more appropriate for a first batch Ausf D at Kursk.

It was the type also of the first Bergepanther, based on these early D.

This is the Panther Ausf. D preserved at Breda

Am I correct in saying there were two different types of spiral grills, 1) very early ones designed for the panther prototype engine deck, which has radiator water filler cap right next to the circular radiator fans, and 2) slightly later ones designed for the production engine deck, where the filler caps have all been relocated to just behind the engine in the center part of the engine deck.

The very early ones, when mounted on production panther Ds, were modified by cutting off the triangular projection meant to protect the filler caps. So although the fan grill was round, the edge of the grill had a long straight section where the fill cap protection was machined off.

The slightly later ones were larger, and cast into the final round shape, and were generally round except for a small straight stretch to clear the removable engine cover.

You got this figured out , Chuck ?

here's another pic of what Spielberger says is an A :