Eligibility for 401(k) & Safe Harbor

Just a question, after having a discussion with a co-worker.  Can a plan have different eligibility dates for a 401(k) and 3% Safe Harbor Contribution, or should they match?

I know the eligibility date for a Profit Sharing (or any discretionary contribution) can be different.  I just wanted to confirm if the Safe Harbor had to match the 401(k) or not.

Thanks in advance!

Doesn't have to match, but if it doesn't, you lose your automatic top heavy exemption. Of course, if you have profit sharing contribution, you lose it anyway, so it may not matter.