By "matched", do you mean binned by the vendor for capacity and internal resistance? I don't know of anybody doing that, but dealers like Illumn might be willin

By "matched", do you mean binned by the vendor for capacity and internal resistance? I don't know of anybody doing that, but dealers like Illumn might be willing to sell you multiples with the same lot number. I'd be surprised if most OEMs do more than that when building packs. You can get a cheap analyzing slot charger ($30-40) and do it yourself. That won't be quite as accurate as a big expensive industrial battery tester, but it will be accurate enough to make safe battery packs for consumer electronics.