Yes, without a doubt sandal paste can be applied to Saligrama deities at homes and temples.
It is considered special to offer sandalwood paste if many deities are available states our elders. It is not appropriate to apply sandal to one Murthy and not to apply to the rest; so it is better to apply sandalwood paste to all the deities methodically. Incense and a lighted lamp can be offered to all deities in general, but sandal has to be applied individually after Thirumanjanam.