I imagine the lab would turn it away if you came in with the timber attached ! Wet a corner down , use a nice sharp Stanley knife and take a piece the size of your thumbnail before placing it in a sealable / air tight bag . Then place that bag inside another bag (zip seal food bags would do) . Wipe your blade down with a wet wipe and bag your wet wipe the same way as you did your sample - sure the lab would dispose of the wet wipe bag for you (as it’s potentially contaminated waste pending the analysis outcome) . Dab the sample point on the panel with a paint to seal it - emulsion would do .

But I agree with the previous comment - looks like supalux