Yes, the GS300 AC lines are a direct fit
The 2JZ-GTE VVTi and 2JZ-GE VVTi share the same AC compressor as well. It all just bolts together easily. The only problem you might run into is the line might hit the back of the front mount intercooler depending on how thick it is and how far back you mounted it. The clearance issue is a problem for both the GS3 and GS4 ac lines where it runs in front of the condenser. I'll try to post a picture when I get a chance to take one.
The way I solved my problem is that I just crimped my own AN fittings and tapped in a AN fitting adapter where the line in front of the condenser used to be. Yes, I use race car fittings for my AC in the car