Automatic enrollment exemption if plans merge?

I've got two 403b plans where there is definitely no controlled group and no ASG.  However, they do operate closely together, to the point where employees are shared.  Over the years I've made the plans identical, but now I'm thinking about a 403b MEP.

The main consideration is that the want to continue to not have automatic enrollment.  Both plans are pre-2022, so they are currently not required to offer it, but the way I'm reading the IRS clarifications, if Plan A becomes a MEP by Plan B merging into it, they will be subject to the SECURE auto enrollment rules.  Is that correct?

Thanks.