Dan, if it is factory marked .45/410 then what you describe is the standard configuration for an early barrel. It can take a .410 shotshell. I believe the Hotshot capsules were only for use in .357 and .44 Mag and that they never made them in .45 since there was already a suitable shotshell made (the .410). The strength of the Contender is in the lock-up, and you should be able to fire anything you fire in the Ruger. Reloading manuals lump the Ruger and T/C together as far as maximum loads go. Still, you should work up to those loads since this is a different firearm. I think the problem you are going to have is that the light and short octagon barrel is going to kick pretty badly, especially if you are using a frame with grips of the same vintage as that barrel! Also, I have not personally achieved great accuracy in one of these barrels; the chamber is so long to accommodate the .410 that the bullet may enter the rifling crooked, and accuracy just hasn't been there for me. It would be ok for deer at woods ranges, but that's about it.
Good luck!
RonF