The San Francisco 49ers have done some minor bookkeeping that has affected the contracts of some key players according to resources.Four players have received contract escalators for the 2014 season based on play time over the course of their careers or the 2013 season.Tackle Mike Iupati's base contract raises to $2.770 million. Guard Alex Boone's base salary escalates to $2 million. Fullback Bruce Miller and cornerback Chris Culliver's deals escalate to the restricted free-agent tender number of $1.