Optimization of Between Clause Queries

I have some sql queries involving the use of between clauses, similar to the
following:

select Colors1.*, sum(Colors2.freq) as TFreq
from OldColors as Colors1, OldColors as Colors2
where Colors2.r between Colors1.r - 7 and Colors1.r + 7
and Colors2.g between Colors1.g - 7 and Colors1.g + 7
and Colors2.b between Colors1.b - 7 and Colors1.b + 7
group by Colors1.r, Colors1.g, Colors1.b;

The OldColors table has several indexes, including one that is defined as
follows:
create index RGB on OldColors(r, g, b);

Can anyone tell me with a high degree of certainty whether the jet 4.0
database engine can optimize the above query based on this index?
Does jet 4.0 *ever* optimize queries with WHERE clauses that only consist of
BETWEEN clauses?

Thanks,
KM