Mike tells Ed, "A year ago you had a full head of hair." Later he directs Ed to "remember what happened last year", leading to a flashback in which Ed is as bald as ever.
When Mike is going through the loading sequence for the flintlock musket, he says, "Put the percussion cap on". A flintlock uses a flint to ignite powder in the flash pan which ignites the powder in the breech, causing the gun to fire. A percussion cap is not used for that type of firearm.
Eve identifies the flintlock Mike is holding as a .69 caliber musket. The gun is a Kentucky rifle, which was generally bored for .32 to .50 caliber. Larger bores were generally for smoothbore muskets.