After returning from a NuCamp dealership (160 miles one way from home) I discovered worse cracking on the 1/2” trim piece that goes between the left and right tail lights of our 2017, 320 TAB Q.   The dealership inspected potential sources of a slow leak into the rear compartment of our TAB and concluded it was not the tail lights.   They attributed the leak to a cracked glycol reservoir.   They replaced the reservoir and their assessment of the tail lights is they were not the source of the leak.   Time will tell.   
I wonder if this is a generic RV molding that I might purchase and possible instructions on how to remove the old one and attach a new one?  Thank you in advance for any suggestions!  
Edit:  I searched “cracked trim” and that turned up a bunch of posts, but mostly for the larger external molding that goes over the roof and side walls.   I will contact NuCamp.   

 
                
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2018 Toyota Highlander, XLE
Wisconsin