No thread cap protector included but Ruger sells them for the Gen2’s
https://shopruger.com/Muzzle-Devices/products/2155/
Bolt knobs are replaceable but not sure of thread size as I haven’t tried to swap mine out yet.
Never heard of anyone buying a USPS M/O over the phone but unless something has recently changed the Postal Service doesn’t accept credit cards for money orders, cash or debit cards only.