Nope, thats not it. Same height, but wider connector. Must be some special compaq scsi connector. The motherboard controller is UltraSCSI though.
There are two controllers in this PC, the motherboard one without a RAID, and the Compaq Smart 2DH RAID controller, which has normal connectors.
Internally, the motherboard connector is both USCSI and 50 pin old SCSI.