There is no certainty, like you I find it impossible to spin a wheel up to check for bearing noise against the resistance of the brake caliper, driveshaft and differential, and in the case of the rear wheel rotating the crownwheel, propshaft and planet gears against the other stationary driveshaft, some on here reckon that is rubbish and it can easily be done, I reckon their mechanical experience does not go beyond a keyboard.
Steering to the right increases the loading on both LH wheel bearings and reduces it on the RH ones, if I had replaced the front LH bearing my next one would be the LH rear but I cannot be certain.
I have what I think is diff bearing noise after making the classic error when changing the Haldex oil but its really hard to track down, sometimes at low speed I hear scraping from what I believe is the NSR but without standing outside while someone else replicates the noise I cant be sure, both rear wheels when jacked up seem ok, brake pads wih plenty of meat, no dragging, backplates not rusted or fractured, I fitted my winter wheels this week while sourcing new tyres, now what I thought was diff noise seems louder, maybe its tyre noise and lack of insulation, I have the rear seats and parcel shelf removed permanently.