So about 2 yrs ago, I had one of those firearms trust places write up a trust for me. Silencer Shop just informed me that they listed my wife by her maiden name twice, and by her married name twice on the trust, that I never caught (this is also my first NFA filing). I have emailed the company that wrote it, but have not heard back. Is there a standardized name change amendment I can use? Or does it have to come from the place that wrote the trust.

As a co-trustee or beneficiary, at least with mine, you can add or remove simply with a notarized form provided.
As long as her name is on the trust, I don't see that it would matter about a double post, even with her maiden name. But again, a simple notarized form to remove her maiden name would take care of that.