Guys - thanks for all the updates on the ammo, especially the link to the ammo page.
This 1889 is s/n 98906 built in 1892, so the older GP90 and 90/03 looks like the right ammo.
It looks in great shape, all matching numbers (rear sight is marked 88906 ?) - sadly, it was sported and someone ground the curve off of the top of the rear sight.....