id say no. but i dont know the value of trailers.
but i say that because it doesnt matter if the new axles are new or 20 years old.
if it was that bad of a fire you are going to need to rebuild it to replace the seals anyway. and what about any busshings in the suspension? they will need replacement also.
i would look for a pos trailer of the same style and strip it to get to the same point the burned trailer is at but with out all the fire.