Welcome to Numista!
Here's an NGC listing, with book prices by grade
https://www.ngccoin.com/price-guide/world/austria-thaler-km-1629-1729-cuid-1068889-duid-1219541
I think this is your coin (labeled "modified bust"), but there's also another variety for 1729.
https://www.ngccoin.com/price-guide/world/austria-thaler-km-1617-1724-1734-cuid-1049134-duid-1224171
You should examine your coin closely under magnification to determine which variety it is.
The values for both appear about the same.
Personally I would grade your coin somewhere close to XF, but others may think differently.
Of course actual sales prices are usually lower than book prices.
