It does look like QS 138, I have attached a picture of it.
View attachment 331727
I believe the serial number is on the other side which starts with "QS", if it doesn't then it's possible that it's a clone or the manufacturer ordered them from QS in bulk and requested different serial number format.
Although $7000 seems really expensive, I feel like you could buy and EV swap a gasoline trike for a lot less.