The numbers on bearings are universal. A 30407 is 30mm ID, 40mm OD and 7mm Wide.... etc. etc.. etc....
The country of origin varies, but stay away from China. Low Quality.
Check out Duane Ausherman's treatise on bearings. These things are capable of a billion miles in the right environment.
Dirt, Oil starvation, Heat, water can shorten this expectancy considerably.
Several of the bearings can be had from local sources. There are a couple that can only be found from Motorrad and Benchmark Works.