Interesting marking, if you don't get any answers here post over in the "Spanish handgun" forum on gunboards.
Low serial also according to this
http://en.wikipedia.org/wiki/Star_Model_BM
"BM serial numbers ranged from 1,226,501 to somewhere around 1,942,445"
Very well built and shoot nice. If you really like it your list is gonna get longer like mine did with other Star's
)