Do I have to re-bleed, or what?

I was testing my brake light switch today because I thought it was broken (turned out to be a fuse) and I unknowingly lifted the brake pedal up past its normal resting position. After I pushed it back down I noticed immediately that there was now 2-3" of dead spot before the pedal would get hard whereas before there was less than an inch. Did I somehow get air in the system when I lifted the pedal, and if so do I have to bleed all four wheels? BTW this is a 1970 Duster with the original Kelsey-Hayes manual front disc brakes. The brakes still work and I can drive it just fine but it makes me uneasy having that much play in the brake pedal.