Yes I think "overbuilt" is a very good description for it! And the fat safety valve has a spring in it that must be set to at least 80 if not 100 PSI. I know what the resistance of a more standard 60 PSI spring feels like, and this one is far stronger.
I have posted the photos to see if anyone might recognize it as a known quantity, just in case it might be something special. Otherwise, I will be listing it for sale on the classifieds here, and I will give it until Sunday to see if someone might offer an ID. I did not pay a lot for it, and I have three other boilers already (all much more typical in size).