[RMcNeal]

You are most likely within the margin. Ideally, you would still want to visit a CAT scale with just your truck first, containing whatever you normally travel with, a full tank of fuel, etc. That will give you a weight the you would need to subtract from the GVWR of 12,400 lbs. The remainder is your payload. Then hook up the 5er and weigh again. With the 5er connected, you can get a pin weight based on the difference your rear axle weighs with and without the 5er. You'll want to make sure that this value is less than the 7230lb rear GAWR (rear axle rating). Also, you want to make sure that the overall truck weight is less than the GVWR of 12,400 lbs.
Additionally, the weight of the trailer should be less than its 16,000 GVWR or it is overloaded. Based on your sticker, the unloaded weight of the trailer, before you add any stuff, is around 12,470 lbs. If we assume 20-25% pin weight (just an average), that would mean your truck has 2,494 to 3,118 lbs. added with the 5er hooked up and empty. Your payload sticker, the last one with tire info, says you have 4407 lbs payload on the truck, which means you're likely ok.
All of this has a lot of assumptions, so CAT scale tickets with just the truck, and with the truck and 5er would give you real world numbers. The biggest thing to remember is that anything you load in the 5er or truck would add to the numbers, including passengers. Also, if you can get weighed on a CAT scale, you can get individual axle weights for the 5er. Each axle is 7,000 lbs rating. Loading stuff in the 5er and riding nose high or low can all effect how much weight is on your truck, and each axle. With a SRW, you don't have a huge margin. Many will say you need a dually, but realistically you are likely OK with your SRW truck. Just don't overload the truck or 5er.