Although Andrew is right about David Byrden's site being the best reference for German interior colours. The 38(t) was a Czech vehicle and I believe that the Czechs carried on using their own colours.
I spoke to the owner and restorer of this vehicle at the War and Peace show last year:
The vehicle was dug up in Hungary and was overall dark yellow on top of the Grey. The numbers were visible under the paint, so he restored it to the colour and markings under the yellow paint.
The interior was "white, off white" I asked if he would describe it as ivory and he said no, also he is restoring a Marder 3M which also has a white interior. He couldn't say what colour the inside of the engine bay hatches were because they were too rusty. The tools were original spares which were packaged and marked Pz 38(t) all wood work was green and all metal work black.
Hope this helps.
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