The idea has been done before, in the early days with Contender barrels. No idea how successful it was though, before the Internet days. Seems it didn't stay around very long if that says anything.
It is an option for your Encore. But it raises a question I'd ask first... was the barrel test fired after the last return to assure it shoots accurately? At $100 a pop with what used barrels sell for, not the $300 savings advertised to your door, and you probably already have a forend. Add the return shipping, not cheap now days insured, and the possibility it won't be considered in the same condition when returned adding more cost.
Not to put the idea down at all, hope it does become a viable option, just suggesting that you become informed before you jump.
There is no charge for this opinion, so maybe its only worth what you paid for it...