To be honest, I would print it in PLA and then make a sand Mold then cast it is Aluminium.
But that because i have a forge and know what im doing.
For you, I do not know your skills.
You may be able to apply 'topcoat' for ABS
The same that you would use with resin and Fibreglass, because the Resin is not usually UV protected.
I don't know how well it would stick, but it would be worth a try.
The top coat hardens and protects from sun and I believe has some heat resistance, defiantly weather resistance.