850HK is the oldest E-145, and is owned by TSA. It started life as an E-135 I believe and was converted to an E-145. I heard rumors it was a test bed for Embraer.

If you do some research, you can find some photos of it when it was first off the press as a 135.

Thats an old worn out bird. Ferried it with the gear stuck down once, a turbine tower shaft busted on it in KEWR on one trip I flew, and I seem to recall we had an asymmetrical speed brake deployment on it one time, but that may have been another airplane.