Either of the above reasons why this gun has slightly different barrels could be the actual case (we will never know at this point); other possibilities are that these tubes could have been an odd set "tossed in" by a barrel tube suppier to fill the order, they may have been obtained by purchasing the assests of a defunct maker, they could have been left-overs from the LC Smith Syracuse buyout, etc. Further, and something else to consider, since this is an odd set of tubes, the original purchaser may have received a discount on the gun (as opposed to paying a premium) simply because these barrels were slightly out of grade. Personlly I believe these barrels are some type of laminated steel (which was used on some early Syracuse made Smiths, although I have not seen this particular pattern before); but the primary point to remember with your gun is that these old makers, Hunter included, just didn't waste materials; whatever was useable was used in some fashion to generate revenue!
As to restoration, for all I know the gun is "mint" but the photos show mostly used and faded finishes. If you're happy with the gun as is; then leave it as is and enjoy same. The point I attempted to make earlier is that these barrels, as good as they appear at the moment, would be stunning properly restored in all their original black and white glory. AS to restoration, if you ever choose that course, make sure you have it done by a real pro that (1) knows the correct restoration techniques and finishes appropriate for a period double gun, and (2)that you restore the gun to what would have been period correct options and appearance for this grade (i.e. don't gold-plate the triggers, don't dress-up the checkering patterns, etc). If you did have the gun restored and elected to install such niceties as double ivory rib beads, a Silvers (or even leather pad), and a silver name shield; such items would have been original period options within that grade, so would not appear out of place, and (properly done) would improve the finished appearance of the gun. Would it be cost effective to have such a restoration? Almost assuredly not. If this were the typical damascus barreled 0E or 1E would I restore the gun were it mine? Absolutely not (this one is just a bit more special). Is it unethical to restore the gun? Certainly not as long as (1) you don't respresent the gun as having original finishes; and (2) you have any restoration work correctly done (it would be a sacriledge to let some crank butcher an otherwise great example). Best, and thanks for sharing your interesting Smith gun.