Most radio stations suitable for amateurs do not have model approval codes. There is a model approval code in the technical data sheet for radio station license, such as Table 3 and Table 4 in national radio administration bureau. However, you can apply for a license without this code, depending on the specific implementation scale of local management agencies.
You can explain to them that the country allows amateur radio enthusiasts to use their own radio stations without a model approval code.
The code query is on the website of Radio Administration Bureau of Ministry of Industry and Information Technology.