Can I just upgrade to 5200 pound axles ?

OK surprise package here...well if anyone has been following, I'm building a...well I am an RV person first and I built the house I live in, about 98 percent of it. I refuse to call my project what it is but it is an RV in my mind not some overweight trendy thing with wheels. It will be towed, always portable and functional used on weekends with tanks you dump if that makes any sense. My RV education started with the truck camper...now trailer talk. I can't thank you all enough for giving me a good throw under the bus but I need to learn this stuff from the ground up and your all doing a good job at it...so thank you. Since I acquired this thing not knowing anything...I'm defiantly getting a schooling from the ground up...but that is where it starts from the ground up and that is why we are having this great conversation....but everyone learns something here and that too is awesome!! Many more conversations to come. Thank you roy67ss...do you think this is what they did? Now that is a great piece of advice...so your thinking they are 5200lbs axles with smaller tires (15) instead of (16)...hence the 12 inch drum package and possibly a smaller spring pack? Outstanding advice...so they just retagged them at a lower weight rating when they saved more by putting the smaller tires on and possibly the smaller spring pack?....I need to get some dimensions of the tube and count the springs right?