unknown cheapo ABS - PETG is ok
I made one in PETG, sanded and painted then, ABS... for the win! With a dome top sanding and acetone make a smooth finish. The original plugs (and bumper) says Steel Horse Automotive 73mm or 2-13/16" ID for bumper in my case, scale as necessary.
The ones "with support" have a disposable inner circle and brims to keep ABS from warping. But you can use that with you favorite material also.