Hi electron,
I agree with mainah's reply. I'll add some to it. Do you know if your axle is a torsion axle (aka rubber ride) or is it leaf springs? If leaf springs there is an easy way to check if you have positive camber like you are suppose to.
Regardless of axle type, there is a simple level check. You need to find a hard surface drive way/pad that ideally is level to start with. And check it with a 2 foot or 4 foot level that is is level.
Park the camper on the level surface.
Then use the level on the side of the rim. Space it off the rim with 2 pieces of something the same length/width. Even a 2 x 4 block will work just so the level is not touching the tire. The rim is what you are after. See here. I used 2 deep sockets the same length and clamped it in place. Do not need the clamps if you have a helper hold the blocks.
The top of the tire/rim should be tipped outward from the side of the camper. That is positive camber = a good thing.
If the level is true plumb, that means the rim is square with the level ground. That is 0 camber. Means all your camber is gone
If the top of the tire/rim is tipped inward from the side of the camper, that is negative camber = a bad thing. Negative camber means the axles are generally overloaded to the spec they where made for.
Have you weighed the axle weights yet? It is easy to be over weight on a camper if you are not counting calories... A truck stop has a scale that you can pull on and weigh the camper axle with for about $7 to $10 bucks. Make sure the camper has all the camping gear, food and water in it that you tow with camping when you weigh the trailer. Compare that axle weight to the axle rating on the VIN tag on the front left of the trailer. It would be GAWR = Gross Axle Weight Rating. If you are over, then the camber can be all used up and either 0 or negative. Need to remove the excess weight and the axles "might" come back into alignment if they are not permanently bent. You can do the level check again to see a change.
Excessive "toe out" can create the inside edge wear too. And there is a way you can check this too if the camber checks out OK. You can do it with a tape measure or a feeler stick. Let me know if this is something you want to check, I'll type some more.
You asked about can and axle be reversed 180, If you have torsion axles, for sure no. They will not fit.
If you have leaf spring axles, you can physically rotate the axle 180. 180 meaning spin it to put the left side on the right and the right side on the left. Spin the axle as looking down at the floor of the camper. The front face of the axle tube was facing forward and is now facing backward. And some install them wrong too as you can physically do that. The problem is, when the axle is built they put either 0 toe or very slight "tow in" in the axle spindle. If you flip the axle 180, that slight tow in becomes toe out. Excessive toe out wears tires. So while you can do it, the results are not good.
Before you go to the trailer shop, weight the axle. If you are overweight that has to be corrected before they can bend align anything. Or worse they align it in an overloaded condition which is bad.
If you have never weighed your camper, do not feel alone. Most folks do not even know to do that. But if you are like me or most any other camper, "stuff" keeps coming into the camper.... 5# here, 10# there, need more stuff here, another 20# and before you know it you are over the axle ratings. It is a classic camper problem. Don't feel bad if you are overweight, you will be like the rest of us until we realized it.
Hope this helps
John