Factory Maverick 88s feature a black, synthetic only stock and forearm, cylinder bore (although interchangeable chokes are available on some hunting models), and cross-bolt safety.
Maverick 88s do not come equipped with any sling mounts (except the security model), as the Mossberg 500 series does.
Also the Maverick 88 does not have a receiver top pre-drilled and tapped for a Weaver scope mount rail.
Maverick 88s are factory finished with steel bluing only, whereas Mossberg 500s have factory-blued, nickel-plated or parkerized (barrel/magazine) options.
Security models come in black or Flat Dark Earth stock and fore-end.