TN Visa - are weekend hours okay?

I am going up to get a new TN status soon and I think it is going to be easier (cheaper) for me to fly up on a Friday and then return early Sunday morning. Is it okay for me to go for a TN on Sunday morning? I will have all of my docs in perfect order, reviewed by an attorney, etc. I noticed on a previous post someone mentioned that they had to call and verify the job offer with the new US employer and obviously, that couldn't be done on a Sunday - so I am wondering if things have changed and you have to do it when they can call your employer or if it is okay to do it anytime still?

Thanks in advance!

They don't call.

If there is a flight on Sunday, they are open for TN approval.