First thing due to the extensive restoration the rifle is more a user than an investment piece.

As the ejectors aren't working properly during your evaluation period, negotiate a longer period, for an independent DR gunsmith to check it over. That person can also advise on any additional repair costs needed.

If they won't do that, send it back.

If they agree send it off to get checked properly.

After all they told you the ejectors had been fixed and they aren't.