So, in the body of the pattern, the instructions for the selvage on the wrong side should read *sl1, k1* instead of *k1, sl1*. That is, the stitches that are slipped on one side should be knit on the other side. But if you follow the instructions as written, you end up knitting and slipping the same stitches every time, because the selvage is worked on an odd number of stitches. The collar is worked on an even number of stitches, so it should be OK.
Sorry for being an idiot! I can’t believe I didn’t catch this. Man, I suck.