Well I found the pickup in the 09 range to be quite scooped so not sure it would bring out the best of flats. Although I’m a rounds player I still swapped out the pickup in my 08 to a Tonerider, which sounds very much like Fender Custom Shop 62s, but at a third of the price. So really I’d go for whichever Precision feels best to play, put on your fave flats then if there’s anything lacking in the sound look at a possible pickup or string change, changing one or both of these can make a lot of difference. And no, nothing wrong with having another US Precision just for flats.