Not according to Brez. Apparently, I, er... used a little creative leeway when designing them in order to make them more unique. As per Brez, Tholians, although being portrayed as magma based entities, have boarding parties and are allowed to exchange in hostile boarding actions with any other race.
Unboardable SG3ish Thols were quite unpopular, one of the reasons I changed their freighte statusr b4 SG3 went live was to allow for boarding actions so convoy raids would work... I thought I used more than just the idea of them being more unique a race as the reason for their NT special role, but I cant remember now...
But anyway, thats not an issue now that we are going by SFB rules and the Tholians are now being viewed more as crystalline entities than magma based.Makes sense.