45 years...that's wonderful.
I don't know the current price of the Chef's Table but the main dining room increased to $90/person a few months back. Have your parents dined there before? If not you might want to consider the main dining room. It is sooo romantic I think. For a first visit that would be my choice.
For our 23rd anniversary I booked the Chef's Table because I thought my husband would enjoy it. He did very much but we had been a few times before. It's interesting, lots of personal attention and detail on the food...just not as romantic as the main dining room IMHO.
Whatever you decide...what a great gift!