Yes, but I won't got it before this summer since it shipped to my parents' home in China
Actually you can contact to "Hardcore Expert" here to buy a serial card, he is the designer of this computer, and also sell Pocket 386 slighty cheaper than DZT Store.
https://www.aliexpress.com/item/1005006763320985.html
He said the reason for keeping the interface as undefined GPIO was to give hardware developers more flexible options, which could be a serial card, ethernet or a touchscreen interface.
