Those locks were manufactured by many companies, both in the US and elsewhere. I have heard conflicting information that they were initially invented in China or in France. Typically many of them may be set to a particular letter combination but there are some that can’t be reset.
Any local locksmith should be able to determine the combination for you, we don’t comment on opening methods for instructional purposes because of the security risk. The same locksmith can tell if it can be reset or not as well. They generally sell for upwards of $60.00. Hope that helps,
BBE.