I owned a matte 042 which I sold to finance my Smith-Corona M1903A3 rifle - nowadays $340 is a pretty reasonable price, mine was bought and sold for around $250 in '00.
As I understand, the first issue of 042's was made to recycle 642 frames and cylinders - S&W had a lot of mechanically perfect 642 frames that did not match the shade of their stainless cylinders closely enough to meet QC standards at the time, so the frames and cylinders were re-polished and blued/anodized black to present a uniform finish for sale. Also, the model designation was over-stamped "042" to mask the original "642" markings.
The matte 042's were a subsequent second issue, I've heard two stories on them:
1) The matte 042's were made with stainless components and matte-finished to cut labor costs as compared to the high-polished first-issue 042's;
2) The matte 042's were made with blued carbon-steel components.
Of course, on current 642 production, S&W has decided that the cosmetic mismatch between the shade of the cylinder and frame was not a big enough deal to matter.
