The top marking is SR for Sakae-Ringyo (or however it's spelled)
I think the bottom set of markings are MTS-100. Velobase has the MTS 101, which it probably pre-dates.
The only thing to be confused about would be finding replacement bars, seems like most these days are designed for single clamp stem. I guess I'd just mothball the stem/bars in a museum if you needed new bars for any reason.
Last edited by LesterOfPuppets; 12-10-12 at 10:45 PM.