Im not sure if you have access, but the parts catalogs for all NSRs can be found here:
https://workshop.nsr-world.com/

I've also posted a screenshot here for you just in case. All of the honda part numbers are still available so you can be sure you are getting the correct replacement. If you can't get them in Italy, CMSNL in England has them listed. Prices seem reasonable.

Or if you really want to get fancy like I did on my bike, you can get ceramic hybrid bearings in US from:
https://www.microbluebearings.com/

If I remember, at least one of the original bearings had a seal on one side which effectively just keeps oil on the one side of the bearing, but its not used to contain oil in the case. If you end up getting a bearing with a seal on both sides they pop off very easily. The microblue ceramics are delivered with low contact seals and you have to snap them in if you use them. I remember having to do this.

Hope this helps.
Eric
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MC28 SP