suspect that the 16", came off a pistol or bought as an after-market as they are interchangeable.
A 16" barrel could be aftermarket, or it could have come off a TC carbine, or even be a TC rifle barrel someone had shortened, but it didn't come off a TC pistol.
To avoid legal hassle with the ATF TC didn't put 16" barrels on their pistols (contender or Encore) they put 15" barrels on their "pistols" and 16" (and up) on "rifles"
Not that it mattered a lot in the end, TC spent years in court fighting the ATF over the whole rifle to a pistol configuration and back to a rifle thing. ATF didn't care if you turned your rifle into a pistol, but if you only shortened the barrel and kept the stock, OR if you wanted to turn that pistol back into the rifle it once was, they demanded you buy their permission (tax stamp and all that goes with it). Eventually, as I understand it, the ATF lost that case.
The real problem with an Encore .30-06 with a 16" barrel (besides from the ballistic inefficiency of the short barrel) is that it is a light single shot rifle. SO, at .30-06 levels, its going to KICK!. More than some folks want.
Also how the stock fits you (not me) makes a difference too! A bigger difference than many realize. So, basically what you've got in a 16" .30-06 Encore is a short, light rifle that will carry and handle like a dream, and bash the snot out of you when you pull the trigger, delivering the speed of a 22" .300 Savage and the recoil of a .30-06 in a featherweight rifle.
Will kill deer, elk and anything else that walks here, but there's no free lunch, and one way or another, you pay for what you get.