Yeah, it won't grow true to seed. I had a pummelo seedling from a good fruit that grew bitter fruits. Had to bud from the tree next to it to produce better fruits. I'm in a quarantine zone though so don't want to risk spreading anything to you.
I recently learned that Vietnamese pummelo and Chinese pummelo are probably the same thing, but called differently depending on who the nursery caters to. The fruits are pear-shaped yellow with a neck and is low acid with thick membranes.