I don't think it's Gatorboard, but there are many other substrates out there like it which are a little denser, but just because they won't rot or mildew, does not make them essentially exterior products. However, if that small circular cutout near your thumb is where the bolt /fastener went through, it was mounted wrong. There should've been a sleeve going through with a flat head on each side to take the weight off of the material and distribute it more evenly for much added strength. Something, perhaps, you should;ve gone over with the other sign guy and corrected for them. Did this sign have any movement when installed, like from a chain or wire ?? It appears to be double sided with no extra support for anything outside. Big No-No in the sign world when installing exterior signs.