how to pop press-fit cap covering height adjustment on swinging patio doors (Hoppe)

[fair]

My old outswing patio door needs height adjustment (scraping bottom). The Hoppe manual says just pop the protective bottom cap on the set hinge with a small flat head screwdriver and then insert an allen wrench to adjust height. Sounds easy but a smooth surface of hardened vinyl covers everything and the protective cap is flush-mounted with no apparent gaps or notches to wedge it out. I could drill it out to reach the allen wrench slot but don't want to damage the mechanism. What's your advice?