which means if you firewall the throttle on the runway you run a serious risk of over-boosting the engine.
Yes....
The turbo Cessna 207 I used to fly was such an arrangement. Though it had a wastegate, the flight manual conatined a warning that for the first takeoff of the day, great caution had to be used, as overboost was still possible.
While setting up the turbo following maintenance, the shop asked me to begin the takeoff roll normally, and at about 50 knots, for only an instant, firewall it, and note the manifold pressure, but certainly not let it dwell there. On the split manifold pressure/fuel flow gauge, I did see the manifold pressure well into the fuel flow side! It took several of those takeoffs to get the whole system adjusted, so it would no longer do that.
That plane was a homesick angel. After an (approved) overgross takeoff, with quite a bit of somewhat draggy external equipment mounted, and while generating 3 kilowatts of AC electricity all the way up, it still rocketed through 17,500 feet, the intended top of my climb. But, I'm glad I was not paying the bills for the turbo!