It's highly unlikely that you'll see a club with 48º stamped on it.
It most likely will have a 'P' or 'PW' stamped on it instead. The only way you'll know what loft it is is by getting it measured.
The only reason this is important is because PW can be anywhere from 45-49 degrees - so a 45 degree PW will be awfully close to your 9 iron, I imagine.
Another note on your mix 'n' match set of
clubs - something that might make your consistency difficult is the amount of offset each club has. You may have some
clubs with a ton, and some with none. That's going to affect your consistency. I haven't done any research on how much it affects ball flight, but I've seen lots of posts where lots of offset lead to hooks, and none lead to slices (depending on the golfer).