Shinny, mirror-like surfaces and the plating typically extends to the rim sides. Also, plated coins do not have cartwheel luster. On this one notice how the light creates two spokes of the wheel. When the coin is tilted, those spokes will move, just like spokes on a wheel.
Replating steel cents has been around for a long time. As mentioned, they typically are a little too shiny and don't have cartwheel luster, whereas the originals tend be have a more flat luster...almost matte. Sometimes the reprocessed coins have an almost blue appearance, and the originals are more of a silver color. If the roll came from your dad personally I'd rather enjoy not knowing....I'd tuck them away in a dry environment. But since the roll came from ebay I think opening it is the smart play.
No they've never slabbed one still in the paper roll (and it probably wouldn't be a good idea since the paper can be reactive and any outgassing of the paper would be trapped inside the slab) And they probably never would because they would have the same problem that everyone else does, how do you prove the paper roll is "original" if you weren't there watching them roll it after seeing them open the mint sewn bag? I wouldn't depend on that, the zinc plating on a MS steel cent can take on a bluish tint as it oxidizes. In fact that faint blue tint is something I look for on MS steelies.
I'm in agreement with this also as I've only seen the bluish tint on non reprocessed steel cents. The reprocessed ones just look way to shiny and the edge where usually you should be able to see the steel core is plated over.
No sorry also I misspoke as it's not visible on all steel cents mostly just the circulated ones or the replate candidates. With the wear they generally show they should have that darkening corrosion color there where you can make out the core but don't because they've been reprocessed.
OK, I'm really bad about pictures but here is my steelie toner (trying to get the color and iridescence)