No, I don't think so.
You can compare pictures here if you like: (or post a picture of your amp)
http://www.hifido.co.jp/KW/G0101/E/3850-50/C12-67372-46215-00/
You can see the 750a and 720 have the knobs exposed (1020 hides them behind a flap) and internally the 1020 has 4x large filtering capacitors while the 720 (and the 750a) both have 2x.
Anyway, you can just check the bias values at the measuring points (without making adjustments) if you wish. If you are worried, take the measurement and post the value here before making changes.
With amp on, but no signal / volume:
The amp should not be hot if the "Class A Turbo" switch is OFF
The amp should generate heat when switch is ON
5mV is a very safe and low value (remember to set this with the turbo switch OFF) so there is no harm in setting to this value regardless. Just make sure you measure at the correct test points and be careful not to slip with the meter leads as if you touch anything else you could destroy the amp.
Even if it was the 1020 (which I believe it is NOT), the setting for that amp is 8mV which is very close anyway - so basically - it is virtually insignificant. Finally, keep in mind that the rail voltages in Yamaha service manuals are often incorrect (i.e. they may not be correct for the A-720 either), so I wouldn't use that to judge anything.
Good luck.
