According to the Model 990 FAQ , the 1070 has been developed exclusively for Outlaw (similar to the original 1050), so it and the 990 presumably only share aesthetics (since the 990 is based on the Sherwood P-965 design). That may help explain why the 990 is getting out of the gate a bit ahead of the 1070 - they had to start with a blank sheet of paper on the 1070, instead of an existing platform. I'd figured that the 990 numbering matches up with the 790 amp (since the two share - or will share, in the 790's case) balanced I/O.