AOTC was filmed at 1.4K, not 2K… or at least much of it was. The HDCAM tapes could only record 1080p at 3:1:1 subsampling which is a luma resolution of 1440x1080 (which was cropped to 1440x818), and a chroma resolution of 480x270.
As far as I know, the cams used for AOTC were Sony CineAlta HDW-F900 with Panavision lenses (so called “Panavision HD-900F”), with 1920x1080 effective pixels and 10bits/sample (but 8 bits for compression processing).
You are right about the tapes limitations: the HDCAM tapes were Sony BCT-HD, which provided 2 332 800 samples by frame (=> 2K), divided into 1440x1080 samples on Y channel, 720x540 samples on Cb and 720x540 on Cr. But the HDCAM codec used rectangular pixels, so the recorded 1440×1080 content was eventually upsampled to 1920×1080 on playback.