1) You can ask the dealer.
2) If you are in AC and you are playing at a shoe game with a minimum bet of less than $50, it's likely you are playing an 8 deck game.
you could always get a copy of the cbjn from bj21.com it gives you all the rules for virtually every casino in the country. It cost somethign like $12 for one months issue and it really does wonders.
well the six deck, all things else being equal would be a wee bit better in the neighborhood of circa 0.0280% EV.
often the six deck table will have a shorter plastic discard tray compared to the discard tray for the eight deck tables, obviously by about two decks in height.