I've heard alot about this gun, the South Africa TZ-99, and the CZ-99 from Yugoslavia. All appear to be Sig clones.
The TZ-99 and CZ-99, despite their appearances, are supposedly based on the CZ-75 design -- which probably accounts for the ambidextrous controls.
Gun Tests magazine, in their Handgun Buyer's Guide, has a bunch of tests of CZ-75 clones, and they make a point of including the CZ-99 in that test, emphasizing that it is, in fact, a CZ-design. (They say this despite the fact that most CZs have slides that fit inside the frame, while the CZ-99 is like a Sig, and fits on the outside.)
The CZ-99 and TZ-99 are apparently identical to the DAC gun. (The CZ-75 is an excellent and design, and having a gun based on that design isn't necessarily bad.)
These guns (the DAC included) may simply APPEAR to be Sig clones. I think it'll take a gunsmith with some hands-on experience with the DAC gun and knowledge of the Sig line to really say, definitively, that the DAC is a Sig design.
It surely looks like one.