Can anyone tell me what years and model Zs this plastic trim panel is compatible with? I had the piece listed for a 260z and 280z but was told it doesn’t fit a 260z. Thoughts? 

That is a 280z panel. 75-76 likely. The tall rectangular cut out in the lower left is the difference from the earlier part that fits around the shorter 240z rear shock tower

@Dferr17 So where were they listed? On ebay?

I think those panels are for 76 only.