The only semi-blackened ones I remember from the old days were often Trix/Model Power. Unlike Con-Cor they had the plastic inserts on both ends.
Try this- As Ghengis said, it looks like Atlas. https://secure.atlasrr.com/mod1/itemdesc.asp?ic=22036&eq=&Tp= (sorry; linked to 36" version by mistake)
Shawn, Those wheels are definitely the Atlas MT replacement metal wheels. They came semi-blackened (still shiny like dark chrome) and were early to the metal low pro party, though not named as such like the plastic versions. The ones I dug up from abut 10 years ago are in a 2cmx2cm blister on a perforated card with black, white, and red ink, similar to current packaging. The current Atlas axle width is .553, so these were made for the older Atlas cars, but mainly for replacing Microtrains. Oddly the axle diameter is 1mm, not 1.3(MT) or 1.5 (FVM). To my eye their thick tread face exagerates the tire width and flange, and at the same time makes them look too small. Atlas p/n 22020 for the current .553 Atlas metal wheelsets. I recall seeing some with a thinner or more rounded tread edge, and thicker axles. Is it possible only one end has a plastic insert now? Atlas p/n 22133 for the .540 MT replacements. Pretty much still the same as yours. My favorites for realism are FVM, BLMA, and those from the 2mm Society in the UK. A thin tire edge seem to makes them look thinner and taller, and the flange appear shorter. Eric http://www.shapeways.com/shops/panamintmodels
