CZ made a number of guns in the .32 calibre, but NONE in 9mm prior to the 70s, that I know of. Others in this section, now that I've moved the message, should be able to help.
Does it look like this? If so, its a CZ-27. And its 7.62 mm. After the Germans invaded Czechoslovakia during WWII, they used the guns in their military, and you'll find them with Waffenampt/acceptance marks.
It would have had some collector value if in good shape, but when your great uncle had it nickel plated, any collectibility for this particular gun went out the window. (That's a no-no for collectible guns.) It should shoot standard .32 ACP, I think.
