.... no. It depends on the type of bearing, too. You might not be able to put a spacer on top of certain types of bearings. You have to look at how the bearing is going to take the load top & bottom not just ID/OD.
Also just FYI I ordered several sets of bearings from allballs. You see in the picture I posted I have an XS wheel mounted on the GSXr front end. I'm using the stock GSXr axle, custom machined side spacers, and custom fit bearings.
I ordered the proper ID/OD bearings from allballs and they were 7.5mm OD off and I forget how much off ID. 3 reorders and never got it right. The package gave the right measurements, but the bearings themselves were not even close.
Speaking of wheels.... when swapping a front end you will want to address that, too. What are your plans for wheels? Adapt an XS front wheel to the new forks or adapt a new rear wheel to the XS rear? Brakes? Handle bars? The list goes on.
I used the top clamp and clip on bars from the GSXr. I also used a donor tank and grafted the gas cap into the stock XS tank. So the gas cap and ignore ignition key all match (and it no longer says Suzuki anywhere). GSXr front calipers, R1 rear caliper, matching GSXr slotted rotors all around, R1 pegs... I think I'm swapping wheels. Currently have 18" front and rearear. Thinking of going 19 front 17 rear.
But I digress....