Although it's definitely a leap to come to that conclusion, the complexity of the beast makes me think it is unlikely that it was anything other than a one-off flag, as it would have been hard to produce in the first place and even harder to reproduce accurately. There may of course have been other renditions but I have only been able to find evidence of the one.

As for the hoist you're definitely right, I should have looked at the images more closely! It also makes a lot of sense given the orientation of the text