Can a system field's schema type be used by a user-created custom field?

Hi everyone,

Our app is using the Request Type field of Jira for a feature applying our app data based on the work item types and request types.

In the Connect version of our app, the Issue Created event’s payload includes the values of all fields which make working with JSM projects very easy. But with Forge, this doesn’t happen so we have to call additional APIs to get the field and its’ value.

To identify the Request Type field, we currently filter the field list by the schema type name sd-customerrequesttype. My concern is that a Jira user might be able to create a custom field using the mentioned schema type.

Is it possible for a user-created custom field to use the sd-customerrequesttype schema type, or is this schema type reserved exclusively for the built-in Request Type field?