Sorry, then you think wrong. Most squid species have 8 arms and 2 tentacles. The difference between arms and tentacles is mainly that arms have suckers all the way along their length and tentacles only have suckers at the end. Also, tentacles are generally longer.
Also of interest:
"In mature male squid, one basal half of the left
ventral tentacle is hectocotylised - it ends in a
copulatory pad rather than suckers. This is used for
intercourse between mature males and females."
That from a romantic email from my girlfriend entitled "Let's talk about sex". I love that girl!