I did not read the spec's on the receivers. But a thicker OD receiver vs standard seems a great leap backwards for fitment of parts IMHO. Selectors, axis pins, selector stop plate, receiver cover, rivets.., all would require rework or one-off parts for building. Even folding stock might be a bit wonky on the wider receiver?
A good idea to build one-off parts like noted by 4thIDvet., market for Chinese 19mm front trunnions or underfolder bayo FSB or certain underfolder trunnions or scope rails for a Tantal etc.
But their $350 base kit and all the parts needed to complete is a $800 build at least. Not cheap and no real milspec connection unless one likes the "all american" AK thing.
Not a hater, but maybe the wrong product choices for one-off parts manufacture.