theres a difference in sampling style, but not sampling itself. the west coast has always sampled.
listen to old westcoast albums by: too $hort, ice cube, easy e, nwa, dr. dre, rappin4tay, the luniz, dru down, e40, blegit, 2pac, digital underground, mc eiht, dj quik, souls of mischief, saafir, casual, ras kass, warren g, del the funkee homosapien, pharcyde, cypress hill, the alkoholiks, spice 1, etc.
sampling has always been prevelent in west coast music. one of the key differences is that on west coast albums, they have tended add heavy synth basslines and what not. some of your favorite bay classics are based around samples: i got 5 on it, players club, mack of the year, i get around, dear mama, 93 til infinity, etc.