The BestSeeingWcsSelectImagesTask is gen2-only (the only entry is runDataRef) and the associated tests (test_BestSeeingWcsSelectImages.py only effectively test this code. Looking at the code coverage before and after removing this test and code I get 138 lines covered, 193 lines uncovered before, and 102 lines covered, 192 lines uncovered after. Visual inspection of the coverage html has confirmed that removing the test has no effect on the coverage of the rest of the file.
Further inspection shows a stub of a config file in ap_pipe, (https://github.com/lsst/ap_pipe/blob/b46f7fe300f0a8d1ca96c6fa2c315b16e5b58247/config/makeCoaddTempExp_goodSeeing.py) and Krzysztof Findeisen confirms on slack that "re: the file in ap_pipe, I confirmed that it's a very old file that was not used even in Gen 2 runs of ap_pipe. So there's no compatibility problem there."