Schott 681 sizing help

[Boris.mtdv]

I’m eyeing a couple of Schott 681s on Vinted; a 38 and a 40. I’m 180 cm tall, relaxed chest is about 97 at its widest point. I wear 32 waist in jeans. Shoulders on a snug fitting jacket are 45. Does anyone know whether I’m a 38 or 40? According to the Schott size chart 38 is small and 40 is medium. I’m normally a medium, but I’ve been living in Europe for a long time and don’t know if USA sizes are the same.