Yes! There will be a huge difference between a multi-geared MTB with full suspension and a multi-geared MTB with a rigid fork.

The rigid forked MTB with slicks will accelerate faster and maintain its momentum with less energy being applied.

PS.

Of course, that all depends upon your terrain. If you're on treacherous mountainous rocky terrain, all bets are off! Gimme my full suspension MTB back!

If you're on pavement, you don't really need a MTB. It will only slow you down!