Indian perfume set.

[R. Rankin]

> I think Bob has answered my question.  So
> pre-verbal u- in IO is in fact the same locative
> prefix as MVS o- and OP u- ?

Yes.  The initial *o- > u in IOM is/was originally
a strictly phonological change.  I don't know what
happens nowadays if you have something like ubraN
but then add another prefix in front of the u-.
Does it remain /u/ by analogical generalization,
or does it revert to /o/?  Originally, it
certainly reverted, but this may have changed.
(This is one of the ways you can *appear* to get
"grammatically conditioned sound changes".)

Bob