We've had a lot of those metal shavings, in our third year and now they are getting to be rare. Ours were bright/aluminum, and were definitely from poor cleanup during manufacture, most seemed to be coming from compartments that we couldn't get into, but had sufficient holes that, on long trips and/or rough roads the savings could work their way out. (I think they were primarily from installation of a band that keeps our water tank from moving.)
We do not have a slide, so if yours are similar, they could well be not slide related. I would assume the slide gears are not aluminum, so trying a test with a magnet might give you some comfort that it's might not be wearing gears.
2018 Jayco 195RB
2014 Toyota 4Runner