Hello Millet,
I do not belive that the number you mentioned is the rootstock name. May be it is an internal nursery ore breeders code for anything trifoliate.
E.g. like the CRC Numbers of the Riverside Citrus collection which you can find at the following link:
http://www.citrusvariety.ucr.edu/collection/index.html
In Spain Marisol is mainly grafted on Carizzo.
Regards