I'm guessing because the R33 was only released in 1993 its a series I, fast doesn't tell you that info.
Type M was an option I believe.
If you do a search on these forums im sure you find all the answers, i think the series 1.5 was basically a series I with a Series II engine, you can tell by looking at your airflow meter if it has pink sticker it is from a series II or 1.5.