Named as an RC escrow build it's likely that 7077.0.090404-1255 is the RC that will be modified to 7100 and distributed widely in May. Microsoft confirmed the 7100 path yesterday on its Engineering Windows 7 blog by advising users to modify the MinClient build number from 7100 to 7000 in order to enable beta to RC upgrades.

It is now expected that Microsoft will name 7100 as the RC build and builds 7105 onwards will be the ongoing development branched towards RTM. The existence of build 7105 was confirmed on Monday meaning Microsoft will have skipped (or reserved) builds 7001, 7002, 7003 and 7004 similar to the "skip" from 6956 to 7000 and then the reserved 7001 and 7002 builds for the beta to RC period.