Actually the specifications for the Bold 9700 mention one version with support for four frequency bands:
- 2100/1900/850/800 MHz (Bands 1,2,5/6)
- 2100/1700/900 MHz (Bands 1,4,8 )
However band 5 (850 MHz) and 6 (800 MHz) are not really different frequency bands, but band 6 is just a subset of band 5, which was introduced due to limited frequency spectrum availability in Japan, which forbad using the whole range of band 5.
While band 5 uses 824-849 MHz for the uplink band 6 operates at 830-840 MHz.
Downlink is on 869-894 MHz for band 5 and 875-885 MHz on band 6.
So even the designation "UMTS 800" for band 6 is completely misleading, as it is not operating on a lower frequency than band 5, which is refered to as "UMTS 850".
A phone with support for band 5 does not require any hardware modifications (especially no additional RF-chips) in order to register on a band 6-network, but simply some software tweaks - so I do not count band 6 as a separate one.