Doesn't like to sign.
Early 90s 1972 Team Canada set is his only "certified" auto (I think from 1991?). It's a set commemorating the summit series (now that I think of it, it was probably from 1992... the 20th anniversary).
Aside from that, there never seems to be a large supply of IP cards out there either. I gather he was a little more warm to the idea of signing for people while he was in politics (I can see the conversation now: "Hi, can I have your vote?" "Sure, can you give me an autograph?" "No").
You should be able to find one, but they're not readily available, and almost never cheap.