I think this bass is SC signature model.
But its serial is 87R.
I bought this bass in Kyoto Japan.

Hi Hidehiro,
 
Many of the basses sold to our distributor in Japan were coded with R for Rokkomann (the name of the importer). Later this distinction was abandoned. It appears that you have what we would currently refer to as a Signature Deluxe bass.

Hi Mica,
 
Thank you very much.
My friends, they have three signature basses.
Two SC and one R.
It was mystery for us.