What\'s the differance in the \'87 & the \'88 frames? I've noticed that there are not alot of manufacturers that list any nerf/step bars for the '73-'87 model K5...most state "88-91". Is there a differnce in the frames? I just bought a set of chromed stainless steel step bars for my wife's 2 door Tahoe for Christmas...it's the same part # as for the '88-'91 Blazers....thinking of holding them under my '87 and seeing if they would fit or not. Anybody done this?