1987 4 speed manual

I have a 1987 4 speed manual 5.7 tpi. Everywhere i look it says all 5.7 were automatics and the 5.o had 5 speed manuals or a 4 speed auto. Does anyone know if the made a certain amout of 4 speed manuals for the 350 tpi? Or was it a special order that year? Every site i go to says they dont exsist but i have one.

Maybe someone just swapped in a 350 and a Super T10 from an earlier year. Here is a link showing all options that year.
 
http://www.thirdgen.org/1987-chevy-camaro?s=8316bd1cf68ccd1eb6721fbf3a091291&
 
Definitely no Manual 5.7s third gen F-bodys ever built
 
If you post the first 10 digits of your VIN we can tell you what motor your car originally had. I'm guessing 305/5spd

and 84 was the last year for 4spds so i dont think so.. not factory.