Most classical music is played on acoustic nylon string guitars. Classical fingerstyle uses all the fingers of the right hand. Fingerstyle blues playing is derived from alternating base picking using usually three fingers (thumb index and middle.) All the lesons I ever had were connected to bluegrass and folk style picking. I found they were very helpfull in picking up blues fingerstyle. They are all more alike than classical guitar. I wouldn't say one could not benefit from classical training, but it wouldn't be exxential to learning blues fingerstyle picking.