There was nothing else on the PCB but a power jack. The PCB traces look the same as on Datamath, but there aren't pads for the osc resistor/cap: www.seanriddle.com/tms1043-1.jpg www.seanriddle.com/tms1043-2.jpg
The back of the package had JAPAN - most of the TI chips don't have anything on the back.
The die was labeled 1040A and 1043A. I'll get some die pics up in the next few days.
I guess you could add the extra row of keys and get TI-2550 III.