Should I do a pre harvest defoliation a week before harvest?

A week before harvesting is too soon. The only advantage of defoliation at this point is if you want to save time during the drying process, to have less trimming to do (like when you cut buds to froze them as fast as possible). But doing it a few hours before harvesting is enough.

The diary alreaday shows a harvested plant.. so what exactly are you asking? It is 99.9% certain to be a net negative. LEaves power growth and ripening is growth. Can't make something from nothing. If the energy isnt' there, the plant doesn't do much. LEaves also take in Carbon, which is a major limiting factor along with intensity of light. They store building blocks.. removing leaves will not be a net-positive result on a plant, given common sense context of a healthy plant. Some mass of mildew riddled congested leaves may have a different answer, but the plant is tainted trash at that point anyway. This is something a grower does to make themselves feel more important, but only has a negative effect on the plant. Kinda like flushing at end of grow in absence of any toxicity or real reason to do so. Putting ice on roots, burning theplant, deprivign it of light for long periods of time... all of this stuff is garbage made up by people that don't know any better and focus mostly on feeling proud of themselves.

The one in this picture isn't close to ready. I was just asking for future knowledge.

A week worth of light is gonna do nothing for your lower buds. think about it a week @ 10wks 10%, even less because if its last week u should have the light backed off a bit.

Its going to stress it out, maybe it will put on a bit more frost from the stress but it will need time to recover. Like others have said 1 week is not a lot of time to do anything major. Plus the shock it could get from doing this might just cause it to freeze up and do nothing, thus loosing out on a the momentum it had going. I'd only do this if you feel the buds might rot from lack of airflow otherwise this is a waist of your time and undo stress for the plant when its not needed in the end of life. Good Luck!

A week out isn't going to make a dramatic difference in regards to lower bud quality but it will make your post harvest trimming a lot easier.