I agree the axle and springs look good. But moving forward, you may want to consider replacing it with a current manufacture axle with a larger load capacity, especially if you plan to add any weight to the trailer during your fitting out.
Things that may add weight are air conditioning, a gray water tank, flooring, more batteries, and a myriad of other things that add weight.
I started out with a 1959
Tradewind that was listed as 3200 lbs. When I scaled it after rebuilding and fitting out it was close to 4800 lbs. That far exceeded the capacity of the original axle.
Here is a picture of the old axle, similar to yours, and the new 5200 lb axle.