The reference book, "All 1984-1988 Pontiac Fiero Colors, Codes & Quantities," has transmission quantities for each year. The book is available on Amazon.ca (the Canadian Amazon site will be less shipping cost for you). It is available on any Amazon site, including Amazon.de, Amazon.es, Amazon.fr, Amazon.it, Amazon.co.uk, etc.
For 1986 and 1988, the transmission breakout for each engine and each model is indicated. This includes 1986 data for the amount of V6 engines mated to the late-introduction Muncie/Getrag 5-speed manual transmission for the S/E and for the GT. Not a lot of those were built.