Hmmn, in the course of installing a triple chainring setup my recent FrankenVega build I noticed the the BB from the donor bike (also a Univega, c. 1980 Sportour) was assymmetric. I believe it is an SR BB, as the crankset was SR. As an aside, I originally thought the longer side of the BB would be needed on the chainring side to keep the small chainring away from the chainstay, but it turned out that the shorter side of the BB was adequate and made the chain line up better to the rear cogs, considering that the gearing I implemented was single step plus "granny" (not really a granny, the small chainring is actually 36T).