JT were the first people to make a fan for goggle systems, so yes you can.
However, with a thermal lens, you shouldnt really need one.
Spectras are good...Dye are also good, but there isnt much room in them for glasses, should you wear them...
I wouldnt let a free lens, make me lean towards any goggle system over another.
Try teh popular ones, JT, DYE and VForce Profilers, then buy a set of Profilers liek everyne else does!!! Joke, buy which ever you find most comfortable..Profilers are very easy to change teh Lens on (very, compared to other goggles)..and you could pick up a set for about £30 in the classifides on here.