There were two types of plows for the "K" series locomotives. On the wood beam plows, the shop crew would remove the pilot beam and all. A pilot beam with the ends cut to fit the plow would be installed. I would imagine these beams stayed with the plow when it was removed, as I haven't seen any of these loco running around with the ends cut off the pilot beams. (the CB&Q #537 that ran on the C&S ran its last year and a half with the pilot beam trimmed on each end for a plow.) THese plows are much cleaner looking and have two large nuts (one on K-27's)on each side where a bolt goes through the pilot beams.
The steal beam plows showed up later but did not completely replace the wood beams. On these, the steel pilot beam stayed on the engine. The tube pilot cage was removed and the plow bolted to the pilot. You can see the ends of the beam sticking out each side of the plow and they have sheet metal trim to "streamline" the openings for the beam.