Ouch. Postage would be high as they're original non-folders. Given their age, I wouldn't try to force fold them either to make the packet smaller! Suspect that it would be prohibitively expensive due to the size of the packet rather than the weight sadly....
I mean to say that they "will" fold, but they well over 20 years old now and whilst they are still supple, a few days in a box and I suspect it will split the outer rubber tread and ruin them.... which would be a terrible shame.