[IHateHacks]

A proper tune-up consists of this-

Oil change
Coolant flush/change
Upper and lower radiator hoses
Spark plugs
Spark plug wires
Distributor cap and rotor (where applicable)
Check/set ignition timing
O2 sensor
Fuel filter
Air filter
Thermostat
Power steering fluid change
Transmission fluid change
Differential fluid change
Timing Belt, tensioner and tensioner spring
Check/adjust valve clearances
Compression test
Cooling system pressure test

I know that's alot of stuff, but it really doesn't take too long as long as you have all the right tools.

As far as the MSD wires, thats more of an upgrade than maintenance so thumbs up there. I'd use NGK iridium plugs, again more of an upgrade.

The truth is you CAN'T tell if the head gasket was replaced before unless you have a receipt. You CAN perform a compression test and cooling system pressure test (standard procedure during a complete tune-up), as well as a block test (not so standard procedure during a tune-up) to see if the head gasket is leaking. I'd highly advise you perform a block test if you want to have solid proof it is/is not blown. You need to have the coolant drained to perform a block test so it will go hand in hand with your full and proper tune-up.

Have fun!