An old gun ( this one is probably 70, 90, 120 years old) will not have mirror bright bores unless it was recently honed and polished. Prior to about 1934 all shotgun ammo used corrosive primers, this ammo stayed in circulation until the early 1950's and was hell on bores, causing pitting within a very short time if not thoroughly cleaned shortly after shooting even one shell. It's rare to find one of these guns with original bores, no matter how fine otherwise, without some evidence of this damage. Proper bore honing and polishing in itself is not a reason to reject a gun but I have seen too many that were lapped thick and thin in spots, bored out too much for safety, even oval shaped. Properly done by a real barrel smith it will enhance the appeal and value of the gun although it will have little effect on the shooting qualities with modern ammo with plastic wads and shotcups. I would never reject an otherwise satisfactory gun because the bores "looked too new" but I would certainly use caution.
These guns are beautifully made, even the plainest ones from obscure makers were largely hand made by true masters of their craft, hand fitted to perfection, balanced, finished to a standard that today is only available on very expensive custom guns. As mentioned, the market for these guns is very soft in Canada and a good one could be a phenomenal buy, find one that fits and you will never want to go back to a machine made gun except for dragging it through the mud in a duck blind. On this gun, look carefully through each barrel at a good light or a bright white background and move it around slowly. Look for concentricity from end to end, looking for unevenness, ripples, evidence of heavy honing in one area to remove deeper pits. If it looks like a brand new perfect barrel the work has probably been probably done on a lathe with a pilot by an experience smith and is probably a sign that all is good. This type of work is not amateur work, it would cost $250-$300 for both barrels if done by an experienced barrel smith and is a good sign that the gun overall was worth spending the money on. Still, the head of the stock is the weakest area and this would need to be taken care of asap and should be budgeted for.
12 gauge 2 1/2" ammo is inconvenient to source but it's out there mostly as hunting ammo in shot sizes 6 and 7. Cost is about the same as higher quality 28 gauge and 410 ammo and lots of that gets burned up each year. Cost is not a factor when the gun is only used for hunting and maybe 2-3 range trips per year.