This is speculation on my part.

My prediction is that Don's plaque is the 'original' one. In 1960, Chile changed from an 'old Peso' to an Escudo, valued at 1000 old Pesos to a new Escudo. (I assume some sort of hyper-inflation problem). These Escudos circulated until 1975, when they switched back to a 'new Peso' then valuing 1000 Escudos to a new Peso. (I guess the hyper-inflation wasn't helped by changing the currency name.)

The colour, design and shape of my plaque looks pretty much the same as Don's 1000 Peso plaque. There is evidence that a burr/Dremel-type tool was used on the side with the embedded coin, and then a hot-stamp used to impress 'CIEN ESCUDOS' (which means 100 Escudos).

Then on the reverse, the last '0' in 1000 has pretty obviously been melted off somehow, and the letter 'E' for 'Escudo' hot pressed into the plaque, rather crudely - perhaps with a hot pin or something.

Not an expert, but I'd say Don has a plaque pre 1960 in 'Old Pesos' and I have a plaque from the transitional period, and they just modified the old ones to suit the new ones.

That's my theory.