Yes, if they don't know their surname to be able to say it. Only good manners', which in this day & age is missed greatly.
Had to call my husband 'Sir' when we on Army property, as he higher Rank than I.
I, in turn, was addressed as 'Ma'am' by lower ranks.
If we met at Army Base & I had to 'salute' him, my friends' there thought it was very funny! Yeah, right, ha ha!