One More Oddball Mexico 8 Reales

I did notice those bright spots but didn't stop to think it could be silver wash remains because the fields & devices were so lacking.
I took a closer look.
Thanks for prompting me to pay more attention.
Here's a pic of the castle windows at 100X.
Likely remains of a silver wash.

Did a review of the GNL Gurney database and additionally on my new expanded GNL variety database in my Facebook counterfeit group (~23 new varieties added from group member addition's) and no matches. It's a Non-GNL listed variety. You can give it the next available GNL variety number GNL# 1807-O: Q/R: Mo TH-008. Additionally - Not sure that is trace mercuric silvering as it looks like a crystallized foreign material which from my research is more likely AgCl residue particles. Seen this before in my studies of GNL and regal 8R surfaces. Specifically - Under magnification, silver chloride (AgCl) on a coin's surface often appears as a whitish or yellowish crust, sometimes with a powdery or granular texture. It can form irregular patches or a thin film, depending on environmental exposure. In some cases, AgCl can contribute to toning effects, interacting with light to create subtle iridescence. Mercuric silvering "never" appears crystallized or flaky (i.e., particles flaking off the main body) as this picture at 100X seems to illustrate.

Microscopic analysis, such as SEM imaging, can reveal its crystalline structure, showing fine, needle-like formations or clustered deposits. If the corrosion is advanced, AgCl may appear as a flaky or porous layer, disrupting the underlying metal surface. Its weight at 21 grams, its crude regal type edge (i.e., Inconsistency in its circle/rectangle shaped devices 360* around - any overlaps - appears there is just one? - need two on near opposite sides), its oblong shape (i.e., broken collar?) and its copper, bronze or low zinc brass appearance make it a solid candidate. I will supply the Facebook link with a J. Buck thumbs up. John Lorenzo, Numismatist, GNL Co-Author.

OK. Sent E-Mail to Arthur with Facebook link.

AI yields this = Looking at the 100X (?) magnification image, AI noticed irregular patches with intersecting striations and a dominant orange-brown hue, which strongly suggests oxidation effects—likely from copper-rich composition.

Analysis of Surface Features:
Striation Orientation & Texture

The presence of horizontal, vertical, and angular striations aligns with a mechanically worked planchet that experienced rolling stresses before striking.

The needle-like formations could be residual grain elongation from improper annealing or incomplete metal flow during striking.

High-Copper Alloy & Oxidation Patterns

The coloration points to surface oxidation, possibly from prolonged exposure to environmental factors.

Copper alloys can develop intergranular corrosion, deepening micro-grooves and highlighting material inconsistencies in counterfeit strikes.

Die Transfer & Polishing Marks

The counterfeit die likely had manual polishing, leaving randomized intersecting striations that transferred onto the coin.

These patterns are especially pronounced if the die was reworked multiple times, common among counterfeit operations.

This reinforces the likelihood that this probable high Cu struck counterfeit 8 Reales was produced under imperfect metallurgical conditions, leading to planchet preparation flaws, incomplete annealing, and oxidation-driven surface alterations. But again - with enough magnification no surface is perfectly smooth or uniform. IMO this information does not mean very much with just say 100X magnification view under a standard light microscope. More can be gotten from 20X under a stereo microscope IMO <BG>. JPL

So John, this is another one of those along the lines of what we were discussing in this thread on 2R:
https://goccf.com/t/455808&whichpage=2

where, excusing some sloppiness in execution and some distortion from the mutilation, the design elements are all exactly correct for Mexico 1807 - bust, lions/castles, crown, etc. So necessarily, either a cast - or the theory you mentioned that you, Winston Zack, Jeff Rock are postulating, some sort of early die transfer piece... rather than custom-engraving.

Added a few closer to the Lion & turrets.

Here's an enlarged view of what looks like black fractures above the turret.
I understand now what was meant about the 20X, I do use a stereo-zoom and manipulate the coin by hand for general viewing.
But these odd criss-cross lines caught my attention further along in the OP after looking for silvering.