Two types of 7.65 pistols were manufactured.. depending on the date of manufacture, it would either be the 7.65x21 Parabellum (which was replaced in German service by the 9x19 Parabellum), or it may be 7.65x17SR (which is sold commercially as the .32 ACP). Mauser manufactured pistols in both calibers.
If you're referring to the Mauser rifles, what you have is probably one of the Argentine Mausers (they made a number of different models, with the Modelo 1909 being most common). These were manufactured in Germany for the Argentinians, and fire a 7.65x54 cartridge. Surplus ammunition for this rifle is a bit uncommon, but still can be found if you search in the right places.
any 45 cal ammo will work in a 45 cal pistol
No.
NO
Yes it is
I have a model '66 and the round type is .25.
22 mag rimfire. say it on the gun.
No.
yes
No such caliber as .32 Special. Use the caliber of ammo marked on the gun.
45 ACP. Have it checked by a gunsmith before firing.
if it's a revolver......32 cal revolver ammo if it's a pistol......32 cal pistol ammo
marlin 35 cal. lever action. rifle/ Marlin makes the rifle ,but not the ammo for it.