BurkeyII,

F100s do have thrust reversers (clamshell-type, like on the DC-9 series). They also have the speedbrake, which is one of the easy ways to identify the Fokker twinjets.

CO used to do the thrust-reverse pushback from gates much more than they do now. Based on lots of circumstantial evidence (for another day, if you're interested), I'd say they stopped doing it because it's not a great thing to do to the engines. They tend to kick up a lot of dirt and such, which then gets sucked into the intakes. I haven't had a CO thrust-reverse pushback in two or three years.

NW does it at their hubs with all of the DC-9s, AFAIK.