Got a 51e curado sometime back and remembered I was able to spin the handle backwards a couple times but when I can't seem to make it happen again. Could this be my AR bearing going? If so, is it an easy fix? I have no problems with basic cleaning and drag/bearing swaps but never done anything more.

Make sure the AR bearing isn't over lubricated. (It's incredibly easy to do this and it will cause the slippage you are speaking of). Pop it out from under the handle side under the drag and give it a check . Make sure it isn't missing any of the "spokes" inside the housing as well. 

The 2 Curado 50E I bought brand new had issues with the AR bearing. It would slip and I would be able turn backwards until the pawl caught it. Take a q-tip and gently run it around the inside of the bearing to pick up excess grease and it should be fine. If that doesn't fix your issue, you'll need a new bearing. I don't think they can be fixed.

OK cool. I'll Crack it open in a bit. I got this one used at a good price so it really wasn't a surprise to me. Kind of a budget finesse caster project on the back burner.

That bearing is supposed to be bone dry, right?

Never grease, a Q-tip and very light oil is all you want to use, but grease and heavier oil is a no no.

There good little reels.. Hopefully it's not a failed AR bearing, though.. I hear more over lube problems x10 than bad AR Bearings good luck