Krause list the Chile 1808 FJ 8 Reales at $250 in VG, $350 in F, $450 in VF, and $750 in XF. That's with Charles III. The FJ with Ferdinan however is $2000 in F. The one showing is Charles. $1200 is way too much for that coin.
Yes, 1200 USD seems high. 1808 is a scarcer date within the Santiago mint Charles IV 8 reales series, mostly 1800 and 1801 seem to be offered. But still too high. In that condition about 500-700 would be fair. You can check here : www.mcsearch.info for relative scarcity of various dates, and actual prices paid. Derick, besides Sedwick in the US, Aureo and Cayon in Spain are good sources for Chilean colonial material.
It's also one of the known counterfeited years / mints. Those dentils don't look even to me and the wear pattern in the toning is weird. I wouldn't buy a coin of this scarcity unless I was 100% sure of the authenticity and could see it in-hand.
Yes I agree the coin looks suspect in those photo's and I would suggest that if you have a continued interest in this piece, that you communicate well with this seller and ask for verifiable references. What if anything can you tell us about this seller?