No offence intended Chris!
No, you don't have to "re-harden" the pipes. Work does that for you in the form of heating and cooling, and age for that matter. Hence it being better to use fresh pipe stock if you can get it. It's not age hardened already.
You might just notice that I have covered my own gawdy silicone hoses with inner tube offcuts too!
They were already purchased for Frederics car and too expensive to throw away so I covered them so as not to offend my eyes!