It’s a 2004 Gen III. I always ran Mobil 1 10W30. So I have to have flow but it’s taking longer with 0W40 to build adequate pressure. I had a short drive today, it took what seemed forever to build pressure on 1st startup, on the 2nd it popped right up - but the oil was warmed up at that point.If your dipstick is showing okay I think you're likely fine. Realistically speaking the oil quantities in the manual assume a dry engine I believe, which you'll never really be able to get in practice with a standard oil change. There is always going to be some residual in the engine, and as big as our engines are that could be a reasonable amount. I assume you checked after you ran the car as well? The oil filter can hold a surprising amount of oil I've found. I never used to prefill them before I had the Viper, but have gotten more in the habit of doing that, at least on cars where it's easier to do (like something with a vertical filter).
My oil pressure light is similar, even just with day to day use, not only on a change. Do you have a gen 3 or 4? When I did my rebuild I changed out to gen 4 style main bearings. They have a longer oil groove to keep oil going to the rods for more of the crank rotation, but that leads to less oil pressure at low rpm at least since there is less resistance to flow now. I used to idle at 50 psi, but with the new bearings it's more like 20-30 when warmed up. I guess what I'm getting at is that lower idle pressure would take longer to put out the oil light I would expect, so you might still be getting flow just fine, but not necessarily the pressure.