Yes, the primary side switching transistor would give a good hint.
If it is rated for at least about 600V, IMO this is an universal input power supply.
CS10N60F A9HD, rated for 600V
OK, next step would introduce real testing:
Run it from a variac, starting at 110V, with nominal load applied.
Watch the waveforms at the drain of the primary transitor and at the secondary rectifier diodes.
Ramp up slowly the voltage - peak reverse voltage on the rectifier will rise, also peak voltage at the drain.
Watch for anomalies like clipping, oscillation or voltages execeeding the ratings (of the MOSFET and the rectifier)
Try the same at no load condition.
If you don't have the tools, either be brave and just turn it on on 240V and watch what happens or run it off 120V.
Removing half of the primary rectifier wouldn't reduce the peak voltage, just puts more ripple current on the input capacitor and undesirable DC on the AC input.