Without seeing more of it and more details I can't say for certain if it's been repainted but I'm leaning towards a yes. The seam sealer at the tub corner isn't very uniform, (recessed in the seam and then becoming flush at the last couple inches). Not that the factory paint job is high quality to start with, but this has me thinking it might be a repair. Either way you need to dig the seam sealer out (a wire wheel on a grinder makes short work of it), then get the rust out as it's also comes from the backside and reseal and refinish. Look from the underneath behind the wheel well to see this seam from the backside. Chances are you'll see the pinch welds with rust in between. You'll need to clean this up and seal it from behind to slow it from reoccurring.