I'm sure there is is. I don't know if it's an rpm/gear dependent one, or if it's just speed-related but I am almost positive there is.
For top Speed I am not sure. I know with 245/45/17 tires (which I have for summer rims) my little Sixer's T-5 should max out at around 200 mph at my redline of 4800 in 5th gear. I can hardly see half of that, but that's what it's capable of.
There most certainly is a speed limiter in stock trim, it's called a lack of power. You will run out of power long before redline in 5th with a stock long block. I would also call it a gamble to take a 11yr old car to top speed if it still has the original suspension. Then there is the extreme stress that topping out a car has on the engine. If you're built, have fun, if not, don't do it.
96-98 Cobras are governed to about 152mph. Terminators to 155mph and GT500's to 155mph also.
Keep in mind the speedo's aren't all that accurate. The limit is easily changed by your tuner. It's not elliminated just moved. Mine was moved to 199mph so it's basically gone.