Painting over a repaint

I’m replacing some rusted and wrecked parts on my RamCharger. It was originally red, then painted with a single stage gloss black. The parts I’m installing are tan and look to be a factory paint.
I’m wanting it two tone, black and B5 blue, with a clear. Not trying to make it a show truck, just nicer than it is. I’m going to attempt to do it in my driveway, so I’m not expecting it to be perfect.
My question is, do you think the fresh paint would stick to the single stage repaint if I hit it all with a light sanding or a scotch bright?
My plan is to paint the new parts with a single stage black and bolt them on, and do the blue, and clear later on. Is this a stupid idea?
Thanks, Craig.