The "410 Gone" is a status code delivered in the HTTP header, and has no relationship to what is shown to humans or bots on the HTML page. You can deliver any 2xx, 4xx, or 5xx status code in the HTTP header before the HTML page is served.
Are you saying that a 410 in the page header is entirely different from and unrelated to a 410 generated in the .htaccess? I hope so, because otherwise it becomes another of those "it's at the whim of your server" issues.
The OP did specifically say they didn't want to go the .htaccess route.