The workbench that Kelly completes has three boards that form its work surface. However, when Al and Jefferson emptied the contents of the box earlier in the show, there were only two boards.
When Al is turning on the flashlights that are hanging from the ceiling buck is behind him laying in the kitchen. A few scenes later after Al has put the flashlight on Jefferson buck is now on the stairs. There was not enough time for buck to move from the kitchen to the stairs..
Some of the pieces of the workbench that Jefferson were examining were actually joist hangers (painted black), and would not have been necessary for the construction of the workbench.
The idea of Al not being able to put the bench together is the opposite of the earlier storyline where he could fix his car, build his own bathroom, and when converting the garage into the man cave.
The caption under Dan Quayle lists him as 'Last Years Winner'. The Alpha group would never have made such an obvious grammatical error (omitting the apostrophe in 'Years' to make it possessive).