Checking If Date Is Entered Ok

I have to enter date into cells. It is being written from the lists of paper, where for date is entered only year (e.g. 1987), but I have to enter it into excel with day and month (the program working with data only recognizes this form; eg 01.01.1987).

I was thinking of writing a conditional formatting, to remind if I will forget to write 01.01. before year.

I prepared formula like this (to check for the dots):
=IF(AND(MID(AD2;3;1)=".";MID(AD2;6;1)=".");1;0)

But it is not working, because the function recognizes general formatting of cell instead of date formatting (28491 instead of 01.01.1987).