Was the millisecond pulsar in SN1987A spun up or born spinning fast?

It is argued here that the millisecond pulsar in SN1987A has been spun up by accretion. The accreted angular momentum in this case comes from the mixed mantle and helium core of the ejecta, of which roughly 0.1 solar mass fell back during the first day after the explosion. This sizable mass, and hence angular momentum, of the reimploded material is at least partly a consequence of the blue supergiant nature of the progenitor star.