So I finally pulled the good spring off... measures out to 25.25 eye to eye. Gonna need new shoulders bolts anyway as those mostly were trashed removing them, I plan on a wet bolt/shackle kit anyway.
The stamping on the spring band was:
RA 93115
7 29 04
I might assume the second number is the date it was stamped
A search does bring back a matching hit:
https://standardaxle.ca/product/spring-25-70-4-leaves-72-26a-sup/But those are rated at 3K, so, who knows. The number I found on the axle was 5200. The number on the RV is 5080 per axle, so, ha, none of it lines up. Either way I think I'm going with 3K springs.