Is this grid fin piece a standard LEGO brick? I'm trying to identify the circled part from this MoC, but I haven't been successful in doing so. On the one hand, the creator of this has called out two other parts in it (not shown here) as being modifications of existing bricks; but didn't say anything about the one I'm asking about, and the spacing in the grid looks about the same as in a LEGO fence piece which makes me think it might be a standard brick after all.
The original source for the MoC appears to be this post on Facebook. Not having an account there, I can't ask the designer directly.
I think that is
Part# 30046 :
Window 1 x 2 x 2 2/3 Pane Lattice Diamond with Rounded Top