Actually, that plate (#49, loaded chamber indicator nut) does act as a barrel stop in the 97B. In fact, the screw that holds #49 in place is listed as a barrel stop screw (#65) in the manual.
Absent the plate, the rear of the barrel will slide too far up the breechface when the slide returns to battery, thereby jamming the barrel hood into the ejection port.
I would advise against shooting your 97B until the relevant parts are replaced. Since the parts flew off in the normal course of using your 97B, CZ-USA should most likely send you replacements for them under the warranty. A little bit of blue (medium-strength) Loctite in the future would help retain the barrel stop screw.
DL