Identification help Philippines quarto?

Apologies for its sad condition. I think it is Spanish Philippines quarto KM-7 1817-1833 (the other side is completely unreadable) 21mm 3.75g. My question is that in the shield, the castles and lions are reversed - is this a known variety or possibly a counterfeit? Thanks!
Edit - I found a picture of an 1830 with the shield like this, so looks like a variety.
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