I did some digging on the FCC web site. Bel's new GX65 radar detector has an FCC ID of QL4G7GX. Recall that I commented that the GX65's antenna casting appears to be a bit different compared to the standard M4 antenna casting used in the Escort 9500i and other Bel M4 platform radar detectors. I also commented that I suspected that the antenna design is a modified M4 antenna design. Well, now I have some info which seems to back this up.
Here are the test results for the 9500i lab tests for leakage around 12GHz:
And here are the test results for the new GX65 lab tests for leakage around 12GHz:
The GX65 has zero measurable 12GHz leakage! The primary LO frequency has been moved to a different frequency. This means that the LO board design within the GX65 is different than the LO board design used in the M4 platform.