Today, I decided it was time to change the oil and filter, and the air filter, in my wife's 2005 Trailblazer. Having bought this vehicle used earlier this year with about 105K miles, this is my first shot at doing maintenance.

What I found from previous services:

• Missing "plate" and screws covering the access hole to get to the oil drain plug and filter
• Missing "bar" and screws for the brace over the air filter housing

My question ... are either of these missing parts important enough to replace them with either dealer-supplied parts or parts from the 'junk' yard?