[Milsurplus] Engraved plastic ART 13 meter panel

[Boeing377]

I bought a trashed partially stripped but (with great patience) restorable ART 13 for $35 at a ham swap. It was a Navy xmtr and still had the freq card with NAS North Island freqs. No ham mods. What is odd is that the front panel section that has the meters is PLASTIC, with neatly engraved lettering as seen on badges where the engraved letters are white and the panel face is black. I assume this plastic panel was made while in Navy service. Anyone else seen one of these? It is well done and actually looks good. 

73,
Mark
AF6IM