chakra;

If by "front and rear bearing housings" you are refering to the (aluminum) seal housings, then you are correct. Those were painted by someone other than the factory.

The OE Mahle pistons had a small notch in line with the crankshaft axis, which pointed toward front of engine. It sounds like someone replaced the pistons (clean one up and look for an identifying logo....pistons from a number of manufacturers are available)...but a small amount of scoring on the skirts is typical and nothing to be concerned about, especially if you didn't hear any piston slap. Accurate micrometer maesurements of pistons AND block are what you need to determine of you need to replace! If the piston size is still fine for the block dimensions, and you want to reuse them, but those scored skirts bother you, just have the pistons cross-hatched at the skirt. This is a common and inexpensive operation done by machine shops to tighten up the fit, and can get you another 200K miles out of the pistons...until the next rebuild.

Cheers