It seems this signature style was not often used for sketches for people etc., he appears to use his cursive style for those. Snoopy doesn't look quite himself either - his face seems a bit off with regard to perspective etc.. It all looks slow. See what others say.
I agree with Eric's comments. Approach with great caution. Very high risk and hard to authenticate reliably with this signature style. I would not touch it unless it had rock solid provenance. That means real people and a real traceable history. Not grandpa's attic or an "estate sale."