The older 110 will be a Small Shank (same as your 243 Model 12 Barrel). The older DBM units are a little less desirable than the newer ones just because its harder to find aftermarket stocks inlet for the oldest style DBM. The button should be an easy find or easy to have made as said above should you want to retain the DBM. Switching to a Blind mag is a simple swap. Check out this article on mag changes, and read the section for the Staggerfeed Magazines. It's basically that simple. Then just drop it in the blind mag stock of your choice.

Burris rings are good stuff and those older Japanese Tasco scopes are pretty darn decent. I have had 2 so far and both are clear and track well. The aftermarket barrel doesn't hurt anything either. You could sell it here in the classifieds and recoup some of your investment or keep it and try it out, if it doesn't shoot well as is you could always have it set back or rechambered to something with a larger case and have a cheap backup or wildcat barrel. I would get the older one and not worry. Most parts from current Savages will or can be made to fit the older actions, there really isn't that much difference. I personally have fit Accu-triggers to several older 110 actions, bolt heads are interchangeable as are many of the firing pin assemblies just to name a few items off the top of my head.