Gurbachan Singh, 40, allegedly hurled the shoe towards Badal, which first hit security personnel and then touched 89-year-old Badal's turban, police said.
An AK-47 assault rifle, a pistol and over two dozen bullet rounds were recovered from them.
Police have already arrested Bikramjit Singh, an operative of militant organisation Khalistan Liberation Force who was allegedly driving the motorcycle on that day.
The leaders of some Sikh outfits and hardline groups were taken into preventive custody early Wednesday in apprehension of breach of peace after a call that the newly-appointed jathedars would address the community from the Akal Takht.
