It depends on what you mean by "Really Small" and what caused it. Premature babies often need a bit of special care. If the baby has lost weight/isn't gaining weight because they are ill or have some other issue then that could mean special care.
Generally speaking small babies don't need anything extra then larger babies. Avery has always been around the 10th percentile in size. She was only 15lbs at her 9mo check up. Because she's stayed on the same growth curve and has hit all of her milestones the doctors don't really care how big she is. They say she'll just be a small kid.
So I guess the answer is yes and no, depending on the situation.
I have an online friend that has a teeny tiny baby... just barely 8 lbs at 6 months but she was full term and the doctors so far haven't found any reason for her being so small so nobody seems worried :)