I'm confused? Where does it say any of them are 500gs?
This is as per their website:
Part No. MSRP* Bead FT/RR/PR Sidewall/Tread Size TPI Type Weight
260880 46.99 Aramid Dual Black / Black 26 x 2.0 120 Tubeless/Clincher 605g
268970 46.99 Aramid Dual Black / Black 26 x 1.8 ARC 120 Tubeless/Clincher 620g
403689 46.99 Aramid Dual Black / Black 26 x 1.8 120 Tubeless/Clincher 520g
If you've got 2.0" ones, then to quote 605g and you weigh them at 605g you can't complain can you?
I remember them being to quoted at 550g for the 2.0" about 2 years ago when I got mine. Either they've 'reweighed' them or perhaps they've changed the exact spec. a little?
"regular model not acx or tr "
The regular model is a TR (Tubeless ready)
ACX is a completely seperate tyre. The look similar, but are bigger (agonst other things)?